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1.
Blood oxygen-binding characteristics of bigeye tuna (Thunnus obesus), a high-energy-demand teleost that is tolerant of low ambient oxygen 总被引:1,自引:0,他引:1
We found blood from bigeye tuna (Thunnus obesus) to have a significantly higher O2 affinity than blood from other tunas. Its P50 (partial pressure of oxygen, PO2 required to reach 50% saturation) was 1.6 to 2.0 kPa (12 to 15 mmHg) when equilibrated with 0.5% CO2. Previous studies employing similar methodologies found blood from yellowfin tuna (T. albacares), skipjack tuna (Katsuwonus pelamis), and kawakawa (Euthynnus affinis) to have a P50 of 2.8 to 3.1 kPa (21 to 23 mmHg). These observations suggest that bigeye tuna are more tolerant of low ambient oxygen than
other tuna species, and support similar conclusions derived from laboratory whole-animal studies, depth-of-capture data, and
directly-recorded vertical movements of fish in the open ocean. We also found the O2 affinity of bigeye tuna blood to be essentially unaffected by a 10 C° open-system temperature change (as is the blood of
all tuna species studied to date). The O2 affinity of bigeye tuna blood was, however, more affected by a 10 C° closed-system temperature change than the blood of any
tuna species yet examined. In other words, bigeye tuna blood displayed a significantly enhanced Bohr effect (change in log
P50 per unit change in plasma pH at P50) when subjected to the inevitable changes in partial pressure of carbon dioxide (PCO2) and plasma pH that accompany closed-system temperature shifts, than when subjected to changes in plasma pH accomplished
by changing PCO2 alone. In vivo, the resultant large decrease in O2 affinity (i.e. the increase in P50) that occurs as the blood of bigeye tuna is warmed during its passage through the vascular counter-current heat exchangers
ensures adequate rates of O2 off-loading in the swimming muscles of this high-energy-demand teleost.
Received: 12 March 1999 / Accepted: 18 December 1999 相似文献
2.
Bigeye tuna (Thunnus obesus Lowe, 1839) are a commercially important species of tuna found in the Atlantic, Indian, and Pacific oceans. To initiate an
analysis of bigeye tuna population-structure, three PCR–RFLP assays were developed based on the published mtDNA control-region
sequences of four bigeye tuna. Population analyses using these three restriction assays on a total of 248 individuals resulted
in an array of 13 composite haplotypes. A total of 347 nucleotides of mtDNA control-region sequence was characterized for
11 of the 13 composite haplotypes. Phylogenetic analyses demonstrated that the DNA sequences belong to two monophyletic clades.
However, only one of the three restriction assays was able to discriminate between the two clades. The other two assays were
confounded by excessive homoplasy. Both parallel (independent occurrences of the same nucleotide change) and convergent (different
nucleotide changes within the same restriction site) changes of restriction sites were observed. These results emphasize the
importance of DNA sequence-analysis for the interpretation of restriction-site polymorphism data. Analyses of the frequency
distribution indicated that samples of bigeye tuna from the Atlantic Ocean were genetically distinct from those found in the
Indian and Pacific oceans. Thus, these results reject the null hypothesis of a single global population of bigeye tuna.
Received: 16 June 1997 / Accepted: 25 July 1998 相似文献
3.
R. W. Brill B. A. Block C. H. Boggs K. A. Bigelow E. V. Freund D. J. Marcinek 《Marine Biology》1999,133(3):395-408
We measured the horizontal and vertical movements of five adult yellowfin tuna (Thunnus albacares, estimated body mass 64 to 93 kg) near the main Hawaiian Islands, while simultaneously gathering data on oceanographic conditions
and currents. Fish movements were recorded by means of ultrasonic depth-sensitive transmitters. Depth–temperature and depth–oxygen
profiles were measured with vertical conductivity–temperature–depth (CTD) casts, and the current-velocity field was surveyed
using an acoustic Doppler current profiler (ADCP). Large adult yellowfin tuna spent ≃60 to 80% of their time in or immediately
below the relatively uniform-temperature surface-layer (i.e. above 100 m), a behavior pattern similar to that previously reported
for juvenile yellowfin tuna, blue marlin (Makaira nigricans), and striped marlin (Tetrapturus audax) tracked in the same area. In all three species, maximum swimming depths appear to be limited by water temperatures 8 C°
colder than the surface-layer water temperature. Therefore, neither large body mass, nor the ability to maintain elevated
swimming-muscle temperatures due to the presence of vascular counter-current heat exchangers in tunas, appears to permit greater
vertical mobility or the ability to remain for extended periods below the thermocline. In those areas where the decrease in
oxygen with depth is not limiting, the vertical movements of yellowfin tuna, blue marlin and striped marlin all appear to
be restricted by the effects of water temperature on cardiac muscle function. Like juvenile yellowfin tuna, but unlike blue
marlin and striped marlin, adult yellowfin tuna remained within 18.5 km of the coast and became associated with floating objects,
including anchored fish-aggregating devices (FADs) and the tracking vessel. Like juvenile yellowfin tuna, large adult yellowfin
repeatedly re-visit the same FAD, and appear able to navigate precisely between FADs that are up to 18 km apart. The median
speed over ground ranged from 72 to 154 cm s−1. Neither speed nor direction was strongly influenced by currents.
Received: 27 March 1998 / Accepted: 13 November 1998 相似文献
4.
M. E. Lutcavage R. W. Brill G. B. Skomal B. C. Chase J. L. Goldstein J. Tutein 《Marine Biology》2000,137(2):347-358
Ultrasonic, depth-sensitive transmitters were used to track the horizontal and vertical movements, for up to 48 h, of 11
adult (136 to 340 kg estimated body mass) North Atlantic bluefin tuna (Thunnus thynnus Linnaeus). Fish were tracked in October 1995, September and October 1996, and August and September 1997 in the Gulf of Maine,
northwestern Atlantic. The objective was to document the behavior of these fish and their schools in order to provide the
spatial, temporal, and environmental information required for direct (i.e. fishery-independent) assessment of adult bluefin
tuna abundance using aerial surveys. Transmitters were attached to free-swimming fish using a harpoon attachment technique,
and all fish remained within the Gulf of Maine while being followed. Most of the bluefin tuna tagged on Stellwagen Bank or
in Cape Cod Bay (and followed for at least 30 h) held a predominately easterly course with net horizontal displacements of
up to 76 km d−1. Mean (±SD) swimming depth for all fish was 14 ± 4.7 m and maximum depth for individuals ranged from 22 to 215 m. All but
one fish made their deepest excursions, often single descents, at dawn and dusk. In general, adult bluefin tuna spent <8%
of their time at the surface (0 to 1 m), <19% in the top 4 m, but >90% in the uppermost 30 m. Mean (±SD) speed over ground
was 5.9 km h−1, but for brief periods surpassed 20 to 31 km h−1. Sea surface temperatures during tracking were 11.5 to 22.0 °C, and minimum temperatures encountered by the fish ranged from
6.0 to 9.0 °C. Tagged bluefin tuna and their schools frequented ocean fronts marked by mixed vertebrate feeding assemblages,
which included sea birds, baleen whales, basking sharks, and other bluefin schools.
Received: 19 July 1999 / Accepted: 25 March 2000 相似文献
5.
Environmental preferences of yellowfin tuna (Thunnus albacares) at the northern extent of its range 总被引:5,自引:0,他引:5
B. A. Block J. E. Keen B. Castillo H. Dewar E. V. Freund D. J. Marcinek R. W. Brill C. Farwell 《Marine Biology》1997,130(1):119-132
We used acoustic telemetry to examine the small-scale movement patterns of yellowfin tuna (Thunnus albacares) in the California Bight at the northern extent of their range. Oceanographic profiles of temperature, oxygen, currents and
fluorometry were used to determine the relationship between movements and environmental features. Three yellowfin tuna (8
to 16 kg) were tracked for 2 to 3 d. All three fish spent the majority of their time above the thermocline (18 to 45 m in
depth) in water temperatures >17.5 °C. In the California Bight, yellowfin tuna have a limited vertical distribution due to
the restriction imposed by temperature. The three fish made periodic short dives below the thermocline (60 to 80 m), encountering
cooler temperatures (>11 °C). When swimming in northern latitudes, the depth of the mixed layer largely defines the spatial
distribution of yellowfin tuna within the water column. Yellowfin prefer to spend most of their time just above the top of
the thermocline. Oxygen profiles indicated that the tunas encountered oceanic water masses that ranged most often from 6.8
to 8.6 mg O2 l−1, indicating no limitation due to oxygen concentrations. The yellowfin tuna traveled at speeds ranging from 0.46 to 0.90 m
s−1 (0.9 to 1.8 knots h−1) and frequently exhibited an oscillatory diving pattern previously suggested to be a possible strategy for conserving energy
during swimming.
Received: 14 February 1997 / Accepted: 14 April 1997 相似文献
6.
Stomach content analyses are commonly used to study both fish feeding behaviour and trophic conditions. However, the interpretation of such data depends on fish foraging behaviour for a given environment and how representative the stomach contents are to the prey distribution. Tuna feeding behaviour was studied within the context of a research programme conducted in French Polynesia. Tuna prey distribution was characterised using acoustic measurements and pelagic trawls; thereafter, this distribution was compared with the stomach contents of tuna caught using an instrumented longline. Acoustic, pelagic trawling and stomach content analyses give complementary elements to describe the pelagic trophic habitat and to better understand tuna-prey relationships. The classic concept of a reduced food availability for tunas in the tropical pelagic environment seems relative. Tunas able to dive enough during daytime to exploit the migrant micronektonic species secure a source of regular food. This is particularly true of bigeye tuna (Thunnus obesus), which have ecophysiological capacities for this purpose. The behaviour of albacore tuna (T. alalunga), which dive >400 m in depth, remains less clear, as little is known about their vertical behaviour. Lastly, yellowfin tuna (T. albacares), which are distributed in more superficial waters, can better exploit the biomass of juvenile fish and crustaceans exported from the reefs. Analysis of the stomach fullness of tuna caught by longline, a passive gear, generally showed an empty state. This result suggests that most tuna foraging on large prey aggregations present in the study area are quickly satiated and escape longline capture and sampling. A consequence is that studies of tuna feeding behaviour based on longlining may be biased, particularly when large aggregations of prey are present such as in convergence zones. Another potential consequence is that longline tuna catch rates could differ according to prey richness. Longline tuna catch rates may sometimes reflect the relative abundance of prey rather than relative tuna abundance. Electronic supplementary material to this paper can be obtained by using the Springer LINK server located at http://dx.doi.org/10.1007/s00227-001-0776-3. 相似文献
7.
The results presented in this report are based on analyses of 16,721 days of data downloaded from 96 archival tags recovered
from bigeye tuna (Thunnus obesus; 54–159 cm in length, 0.97–5.44 years of age) at liberty from 31 to 1,508 days in the equatorial eastern Pacific Ocean. Analyses
of daily timed depth and temperature records resulted in the classification of the data into three daily behavior types: characteristic,
associative (associated with floating objects), and other. There is a significant positive correlation between the proportion
of time fish exhibit characteristic behavior and increasing length, and significant negative correlations between the proportion
of time bigeye exhibit associative and other behavior with increasing length. For the smallest (54–80 cm) to largest (100–159 cm)
length classes, the vertical habitats utilized when exhibiting non-associative behaviors were 99 and 98% of the time above
the thermocline depth (60 m) during the night, at the same average depth of 34 m, and 60 and 72% of the time below the thermocline
during the day at average depths of 163 and 183 m, respectively. For the same smallest to largest length classes, when exhibiting
associative behavior, the average nighttime and daytime depths were 25 and 21, and 33 and 37 m, respectively. The apparent
effects of the environment on the behavior of the fish are discussed. 相似文献
8.
Dispersal in coral reef fishes occurs predominantly during the larval planktonic stage of their life cycle. With relatively
brief larval stages, damselfishes (Pomacentridae) are likely to exhibit limited dispersal. This study evaluates gene flow
at three spatial scales in one species of coral reef damselfish, Dascyllus trimaculatus. Samples were collected at seven locations at Moorea, Society Islands, French Polynesia. Phylogenetic relationships and gene
flow based on mitochondrial control region DNA sequences between these locations were evaluated (first spatial scale). Although
spatial structure was not found, molecular markers showed clear temporal structure, which may be because pulses of settling
larvae have distinct genetic composition. Moorea samples were then compared with individuals from a distant island (750 km),
Rangiroa, Tuamotu Archipelago, French Polynesia (second spatial scale). Post-recruitment events (selection) and gene flow
were probably responsible for the lack of structure observed between populations from Moorea and Rangiroa. Finally, samples
from six Indo-West Pacific locations, Zanzibar, Indonesia, Japan, Christmas Island, Hawaii, and French Polynesia were compared
(third spatial scale). Strong population structure was observed between Indo-West Pacific populations.
Received: 26 May 2000 / Accepted: 10 October 2000 相似文献
9.
In order to better understand the associative behavior of yellowfin tuna (Thunnus albacares) and bigeye tuna (T. obesus) with anchored fish aggregating devices (FADs), we conducted long-term monitoring of these tuna tagged with ultrasonic transmitters, using automated receivers deployed on seven FADs around the Okinawa Islands. Current and surface water temperature were also monitored by data loggers attached to the stations as a way to examine the influence of these factors on the associative behavior of tuna with FADs. We monitored a total of 52 yellowfin and 11 bigeye tuna at monitoring FADs for a period of 2.5 years. We found that the majority of tuna remained continuously at the monitoring stations for a certain period (max.=55 days) without day-scale (>24 h) absences, until they left the stations completely. The residence time at a single FAD was estimated to be about 7 days, as the half-life for both yellowfin and bigeye tuna. No inter-specific differences were seen, though there was a significant difference in residence time between two size classes: the residence time of the larger size class was shorter than that of the smaller size class. We also found there was a periodicity of approximately 24 h and regularity of associative behavior, estimated based on the fluctuation pattern of the detection rate and of short-term (<24 h) absences. In particular, absences of several hours occurring once a day with high temporal precision were considered to be excursions within several nautical miles from the FADs. These results indicate that tuna express periodic behavior in relation to the FADs and can locate the FADs precisely enough to return to them after a certain time. No relationship was seen between associative behavior and abiotic oceanographic conditions. Therefore, the biological environment (prey availability, the presence of predators, etc.) and the internal state of the individual (hunger, etc.) may be more important than abiotic environmental cues for inducing changes in associative behavior and/or the departure from FADs. In addition, the strong association of tuna with a single FAD and the relatively prolonged residence time observed in the present study may relate to the vigorous activity of FAD fisheries in Okinawa and their utilization of a large amount of bait.Communicated by T. Ikeda, Hakodate 相似文献
10.
Marianne Robert Laurent Dagorn Jean Louis Deneubourg David Itano Kim Holland 《Marine Biology》2012,159(4):907-914
Several lines of evidence indicate that aggregations of yellowfin tuna associated with floating objects are more frequently
composed of small animals than larger ones. Also, the diet of small yellowfin tuna caught at anchored fish aggregating devices
(FADs) around Oahu, Hawaii, was found to shift quite rapidly when these fish reached approximately 50 cm FL. In order to test
for ontogenetic changes in aggregation behavior, we tagged and released two distinct size classes of yellowfin tuna in an
array of anchored FADs around Oahu, Hawaii. Twenty-four yellowfin tuna 30–39 cm FL and 16 yellowfin tuna 63–83 cm FL were
tagged with acoustic transmitters and released near anchored FADs equipped with automated acoustic receivers. Fish in the
smaller size class stayed about 2.5 times longer at individual FADs than the larger fish (mean 4.05 days vs. 1.65 days) and
displayed larger horizontal movements within the array. However, the durations of unassociated phases, residence times in
the entire FAD array, percentage of time spent associated with FADs and numbers of movements between FADs did not show any
difference between the two size groups. The observed size-dependent behavior is discussed in terms of physiological abilities,
diet segregation and anti-predator behavior. 相似文献
11.
Acoustic telemetry was used to examine patterns of activity and space utilisation of coelacanths, nocturnal predators which
spend the day in submarine caves. Nine coelacanths (Latimeria chalumnae) were tracked, each for a period of 1 to 16 nights at Grande Comore, West Indian Ocean. Activities lasted on average 9 h,
usually starting shortly after sunset and ending before sunrise. Vertically, coelacanths moved up and down at and below cave
level by following the bottom contour, mainly between 180 and 400 m depth. The deepest record was 698 m, the shallowest 133 m.
Most time was spent between 200 and 300 m depth. Large individuals performed deep excursions to depths below 400 m, usually
once per night. The fish spent most time in water temperatures of 15 to 19 °C; they rarely ventured into waters warmer than
22 °C measured at depths shallower than 160 m depth. Horizontally, coelacanths stayed in narrow areas ranging from <1 to 10 km
of coastline. Coelacanths are extremely slow drift-hunters with an estimated average swimming speed of 3.2 m min−1, often travelling not more than 3 km per night. They probably take advantage of local upwelling and downwelling and slow
currents occurring parallel to the steep slopes. This study shows that coelacanths are inhabitants of the subphotic zone,
where they are active mainly below the depth of their daytime refuges.
Received: 7 July 1999 / Accepted: 11 February 2000 相似文献
12.
The influence of multiple anchored fish aggregating devices (FADs) on the spatial behavior of yellowfin (Thunnus albacares) and bigeye tuna (T. obesus) was investigated by equipping all thirteen FADs surrounding the island of Oahu (HI, USA) with automated sonic receivers
(“listening stations”) and intra-peritoneally implanting individually coded acoustic transmitters in 45 yellowfin and 12 bigeye
tuna. Thus, the FAD network became a multi-element passive observatory of the residence and movement characteristics of tuna
within the array. Yellowfin tuna were detected within the FAD array for up to 150 days, while bigeye tuna were only observed
up to a maximum of 10 days after tagging. Only eight yellowfin tuna (out of 45) and one bigeye tuna (out of 12) visited FADs
other than their FAD of release. Those nine fish tended to visit nearest neighboring FADs and, in general, spent more time
at their FAD of release than at the others. Fish visiting the same FAD several times or visiting other FADs tended to stay
longer in the FAD network. A majority of tagged fish exhibited some synchronicity when departing the FADs but not all tagged
fish departed a FAD at the same time: small groups of tagged fish left together while others remained. We hypothesize that
tuna (at an individual or collective level) consider local conditions around any given FAD to be representative of the environment
on a larger scale (e.g., the entire island) and when those conditions become unfavorable the tuna move to a completely different
area. Thus, while the anchored FADs surrounding the island of Oahu might concentrate fish and make them more vulnerable to
fishing, at a meso-scale they might not entrain fish longer than if there were no (or very few) FADs in the area. At the existing
FAD density, the ‘island effect’ is more likely to be responsible for the general presence of fish around the island than
the FADs. We recommend further investigation of this hypothesis.
相似文献
Laurent Dagorn (Corresponding author)Email: |
Kim N. HollandEmail: |
David G. ItanoEmail: |
13.
Depth and muscle temperature of Pacific bluefin tuna examined with acoustic and pop-up satellite archival tags 总被引:1,自引:0,他引:1
David J. Marcinek Susanna B. Blackwell Heidi Dewar Ellen V. Freund Charles Farwell Daniel Dau Andrew C. Seitz Barbara A. Block 《Marine Biology》2001,138(4):869-885
Six Pacific bluefin tuna were tracked with ultrasonic telemetry and two with pop-up satellite archival tags (PSATs) in the
eastern Pacific Ocean in 1997, 1998, and 1999. Both pressure and temperature ultrasonic transmitters were used to examine
the behavior of the 2- to 4-year-old bluefin tuna. The bluefin spent over 80% of their time in the top 40 m of the water column
and made occasional dives into deeper, cooler water. The mean slow-oxidative muscle temperatures of three fish instrumented
with pressure and temperature transmitters were 22.0–26.1 °C in water temperatures that averaged 15.7–17.5 °C. The thermal
excesses in slow-oxidative muscle averaged 6.2–8.6 °C. Variation in the temperature of the slow-oxidative muscle in the bluefin
was not correlated with water temperature or swimming speeds. For comparison with the acoustic tracking data we examined the
depth and ambient temperature of two Pacific bluefin tagged with pop-up satellite archival tags for 24 and 52 days. The PSAT
data sets show depth and temperature distributions of the bluefin tuna similar to the acoustic data set. Swimming speeds calculated
from horizontal distances with the acoustic data indicate the fish mean speeds were 1.1–1.4 fork lengths/s (FL s−1). These Pacific bluefin spent the majority of their time in the top parts of the water column in the eastern Pacific Ocean
in a pattern similar to that observed for yellowfin tuna.
Received: 4 April 2000 / Accepted: 25 October 2000 相似文献
14.
European lobsters, Homarus gammarus (L.), were tracked on an artificial reef in Poole Bay on the south coast of England using an electromagnetic telemetry system
which monitored movements between reef units and recorded body movements (pitching and rolling) detected with a tilt switch
incorporated into the transmitting tag. Several environmental variables (water temperature, light, hydrostatic pressure, current
velocity and direction) were recorded simultaneously by the telemetry system, which was self-contained on the seabed. Movements
between units of the artificial reef (excursions outside shelter) were predominantly nocturnal, peaking 1.5 to 3 h after sunset
and returning to low levels shortly before dawn. A marked decline in the number of inter-reef unit movements from late summer
to winter was related to decreasing water temperature rather than to daytime light level, wave height or tidal range. Activity
indicated by the tilt switch was also greater at night, but declined gradually from a peak early in the night to a minimum
at around midday, on average, implying a degree of activity within reef units during daylight. As with movements between reef
units, activity declined seasonally with decreasing water temperature; in addition, the diel pattern of activity disappeared
in winter.
Received: 9 February 1998 / Accepted: 24 July 1998 相似文献
15.
The horizontal and vertical movements of bigeye (Thunnus obesus Lowe, 1839) and skipjack (Katsuwonus pelamis Linnaeus, 1758) tunas within large multi-species aggregations associated with moored buoys or a drifting vessel were investigated, using ultrasonic telemetry and archival tags, along with sonar imaging, in the equatorial eastern Pacific Ocean (at 2°S–95°W and 2°N–95°W). Four sets of observations, each consisting of the concurrent monitoring of pairs of skipjack and/or bigeye with implanted acoustic or archival tags, were conducted in May 2002 and 2003. Ultrasonic telemetry data were not collected until 24 h or more after the fish were tagged and released, to avoid any abnormal behavior as a consequence of tagging. The pairs of acoustically tagged bigeye and skipjack, and also the entire aggregations, were primarily upcurrent of the moored buoy and downcurrent of the drifting vessel during the day. At night the aggregations were observed to be more diffuse, and the fish were feeding on organisms of the deep scattering layer. The aggregations returned to positions upcurrent of the buoy or downcurrent of the drifting vessel at dawn, commonly breezing at the surface within cohesive monospecific schools. The bigeye and skipjack had concurrent changes in depth records, occupying significantly greater mean depths at night than during the day, in most cases. When associated with a moored buoy, bigeye depth distributions were deeper during the day and night than those of skipjack, but bigeye depth distributions were shallower during the day and night than those of skipjack when associated with the drifting vessel. Simultaneous depth records of a large and a small bigeye with archival tags associated with a moored buoy also indicated diel changes in depth. The mean depth at night was significantly less than during the day for the larger bigeye, but the mean depth during the day was significantly less than during the night for the smaller bigeye. The mean depths during the day and night were significantly greater for the larger bigeye than the smaller.Electronic Supplementary Material Supplementary material is available in the online version of this article at http://dx.doi.org/10.1007/s00227-004-1480-xCommunicated by J.P. Grassle, New Brunswick 相似文献
16.
Thirty-eight yellowfin tuna (Thunnus albacares) were tagged with coded ultrasonic beacons between 6 March and 4 December 1996 near two buoys off the western coast of Oahu,
Hawaii. Two to four tuna were captured, tagged, and released on the same day in as rapid succession as possible in an effort
to tag members of the same school. Automated “listening” monitors attached to the buoys recorded when these marked individuals
entered within a radius of ≤1.1 km of the buoys during a 13 mo period. Twenty-seven of the tuna returned to the site of tagging.
The mean number of returns was 4.2 per tuna (max. = 17), and visits ranged from 1 to 910 min (median = 2.7 min, mean = 40.1 min).
The intervals between successive returns varied from 1 to 257 d (median = 3.0 d, mean = 17.4 d). Seventy-three percent of
the tuna returned together with tunas tagged on the same day, exceeding the frequency of returns of tuna tagged on another
day or arriving alone. This social cohesion is supported by the pattern of return visits by five tuna tagged on 6 March at
Monitoring Station R. Two or more of these tuna arrived together on 24 of 35 d when tagged tuna were detected. All five individuals
visited R on 11 April, a month after tagging, three arrived together 5 mo later on 4 August, and three returned 6 mo later
on 1 December 1996. Tuna often arrived at the same time of day, e.g. Individuals 1 and 3 visited R at 09:15 hrs on 12 April
and at 09:00 hrs 8 mo later. The returns were also site-specific. The 22 tuna tagged at R made 182 return visits to R (92.4%)
and only 15 visits to Monitoring Station K (7.6%), 10 km away. An allegiance of tuna to one school, a predilection for returning
to the site of tagging, and precise timing when visiting sites, are consistent with tuna having migratory pathways consisting
of “way-points” that are visited with temporal regularity.
Received: 30 April 1998 / Accepted: 27 October 1998 相似文献
17.
Between June 1994 and September 1996, a mark–recapture study was conducted in the Hinchinbrook Channel area of tropical northeastern
Australia to investigate the movements of the sparid fish Acanthopagrus berda. A total of 962 A. berda were tagged, 922 within a single estuary system, Deluge Inlet. No movements among estuaries were detected. Of the fish tagged
in Deluge Inlet, 12.9% were recaptured. Two movement regimes were detected: local movements (mostly <500 m) during non-spawning
times, and longer migrations (up to 3.12 km) during spawning seasons, to and from a spawning site at the estuary mouth. Although
there appeared to be a major spawning aggregation in the mouth of Deluge Inlet, ripe female A. berda were present in upstream sites, indicating that spawning probably occurs there also. This contrasts to the situation in South
Africa, where A. berda is reported to spawn only close to estuary mouths. Differences such as this highlight our limited knowledge of variations
in the reproductive biology of widespread species such as A. berda.
Received: 25 November 1997 / Accepted: 10 September 1998 相似文献
18.
A. Yano M. Ogura A. Sato Y. Sakaki Y. Shimizu N. Baba K. Nagasawa 《Marine Biology》1997,129(3):523-530
To investigate the role of magnetic compass orientation in oceanic migrating chum salmon, Oncorhynchus keta, an ultrasonic telemetry study was carried out in the western North Pacific off the coast of Kushiro, Hokkaido. Four salmon
were fitted with a tag which generated an artificial magnetic field and modified the geomagnetic field around the head of
the fish. Initially, the free-ranging salmon with stomach-implanted ultrasonic transmitters were tracked for a period of several
hours before the magnetic field was altered for a period of 16 h. The generator produced an alternating magnetic field intensity
of about 6 gauss, with polarity which reversed every 11.25 min. There was no observable effect on the horizontal and vertical
movements of the salmon when the magnetic field was modified. However, it was noted that salmon slowed their swimming speed
significantly before changing direction, regardless of whether the fish were swimming under the normal geomagnetic field or
whether they were swimming under the modified field.
Received: 6 April 1997 / Accepted: 29 April 1997 相似文献
19.
Sixty-eight yellowfin tuna, Thunnus albacares, (60-135 cm fork length) were caught and released with implanted archival tags offshore off Baja California, Mexico, during
October 2002 and October 2003. Thirty-six fish (53%) were recaptured and the data were downloaded from all 36 recovered tags.
Time at liberty ranged from 9 to 1,161 days, and the data were analyzed for the 20 fish that were at liberty for 154 or more
days. The accuracy in the position estimates, derived from light-level longitude data and sea-surface temperatures (SSTs)
based latitude, is about 0.41° in longitude and 0.82° in latitude, in this region. The movement paths, derived from position
estimates, for the 20 yellowfin indicated that 19 (95%) remained within 1,445 km of their release locations. The estimated
mean velocity along movement paths was 77 km/day. The southern and northern seasonal movement paths observed for yellowfin
off Baja California are influenced by the seasonal movements of the 18°C SST isotherm. Cyclical movements to and from suitable
spawning habitat (≥24°C SST) was observed only for mature fish. For the 12 fish that demonstrated site fidelity, the mean
95 and 50% utilization distributions were 258,730 km2 and 41,260 km2, respectively. Evaluations of the timed depth records resulted in discrimination of four distinct behaviors. When exhibiting
type-1 diving behavior (78.1% of all days at liberty) the fish remained at depths less than 50 m at night and did not dive
to depths greater than about 100 m during the day. Type-2 diving behavior (21.2% of all days at liberty) was characterized
by ten or more dives in excess of 150 m during the day. Type-2 diving behavior is apparently a foraging strategy for fish
targeting prey organisms of the deep-scattering layer during the day, following nighttime foraging within the mixed layer
on the same prey. Yellowfin tuna exhibited occasional deep-diving behavior, and some dives exceeded 1,000 m, where ambient
temperatures were less than 5°C. Surface-oriented behavior, defined as the time fish remained at depths less than 10 m for
more than 10 min, were evaluated. The mean number and duration of surface-oriented events per day for all fish was 14.3 and
28.5 min, respectively. Habitat utilization of yellowfin, presented as monthly composite horizontal and vertical distributions,
indicates confined geographical distributions, apparently resulting from an affinity to an area of high prey availability.
The vertical distributions indicate greater daytime depths in relation to a seasonally deeper mixed layer and a greater proportion
of daytime at shallower depths in relation to a seasonally shallower mixed layer. 相似文献
20.
Home range, activity and distribution patterns of a temperate rocky-reef fish, Cheilodactylus fuscus
Red morwong (Cheilodactylus fuscus; Cheilodactylidae: Perciformes), are large temperate rocky reef fish that are patchily distributed in local aggregations
of 3 to >100 fish. The home ranges and aggregating behaviour of red morwong were investigated using external tags (n = 114, over 35 mo) and ultrasonic transmitters (n = 9 over 20 d) at coastal and estuarine sites in south-east Australia. Adult red morwong had a mean home range during the
day of 1865 m2 (SE = 268). Night movement, determined by ultrasonic telemetry, indicated a significantly greater mean home range of 3639 m2 (SE = 416). Home range did not differ significantly with size or sex. Fish movements were greatest and aggregation sizes
varied most during the non-reproductive mid-summer period. Tagged fish (N = 20) displaced 200 to 900 m returned in 1 to 3 d to the point of capture, often traversing open sand habitat and other aggregations.
During the day, fish were commonly found on bouldered habitat. During the night, these site-specific aggregations fragmented
as fish dispersed over a variety of substrata, with crepuscular peaks in activity. Therefore, estimates of habitat-specificity
and feeding patterns collected only by day may give misleading results.
Received: 28 June 1996 / Accepted: 8 July 1998 相似文献