Life cycle of the jellyfish <Emphasis Type="Italic">Lychnorhiza lucerna</Emphasis> (Scyphozoa: Rhizostomeae)

The life cycle of Lychnorhiza lucerna (Scyphozoa: Rhizostomeae) and the settlement preferences of its larvae were studied using laboratory-based rearing experiments. Mature medusae of L. lucerna were collected from the beach of the Río de la Plata estuary, Argentina. This species displayed the typical metagenetic, (i.e. medusoid and polypoid), life cycle reported for other rhizostomes. The fertilized eggs developed into motile and short lived planulae. The majority of planulae settled on the air-water interface (p < 0.001). Of those that settled on the settlement plates provided, no significant differences were observed between styrene slides, glass slides and shells of the bivalve Mactra isabelleana (p > 0.05). No planulae settled on stones. Several hours after planulae settled, they metamorphosed into sessile four-tentacled scyphistomae. Most scyphistomae attached onto the air-water interface. At 19–22°C, the scyphistomae grew up to 22 tentacles and reached 1,500 μm height. The scyphistomae increased their numbers by means of formation of podocysts from which new polyps emerged and strobilated. Strobilation occurred 46 days after settlement. Only polydisk strobilation was observed and each strobila always produced three ephyrae. After releasing ephyrae, strobilae returned to normal scyphistomae and were capable of repeating strobilation. A single founder polyp was estimated to produce up to 60 ephyrae over 4 months. Ephyrae developed into metephyrae 15 days after release at 19–22°C. In this paper we describe the morphological and some behavioural features of L. lucerna in the polypoid and early medusoid stages.     

Abundance,distribution and prey composition of scyphomedusae in the southern North Sea

The annual cycle of abundance and distribution of the scyphozoan medusae Aurelia aurita, Cyanea lamarckii, C. capillata and Chrysaora hysoscella were studied in the southern North Sea in 2004 and 2005. Three different patterns of seasonal occurrence of medusae were distinguished: (1) the early occurring C. lamarckii (February–August), (2) C. capillata and A. aurita (April–August) and (3) the late appearing C. hysoscella (July/August–September). Cyanea lamarckii was the most frequently encountered species in this study; its highest mean abundance was 1.8 ± 2.7 ind. 100 m⁻³. The prey spectra of C. lamarckii, C. capillata and C. hysoscella contained several copepod and other crustacean species and thus make them potential competitors with fish larvae. Medusae in this study also consumed fish eggs and larvae, including clupeids, in all months analysed. Although peak spawning of sprat (Sprattus sprattus) coincides with the maximum abundance of medusae (May–June) the relative low abundance of all medusae species in this study makes jellyfish predation unlikely to be a factor controlling sprat recruitment in the time frame investigated.     

A comparative ecological study on the scyphozoans Aurelia aurita,Cyanea capillata and C. lamarckii in the Gullmar Fjord,western Sweden, 1982 to 1986

During the years 1982 to 1986, the life cycles and population dynamics of three scyphozoans, Aurelia aurita (L.), Cyanea capillata (L.) and C. lamarckii (Person and Lesueur), were studied in the Gullmar Fjord on the Swedish west coast. The settling of planulae, strobilation of scyphistomae and release of ephyrae were followed on ceramic settling plates in the laboratory and in the field. Weekly to bi-weekly hauls with Bongo nets were used to study the abundance of ephyrae and medusae. The results show great differences in the life cycles and ecology of the three species. A. aurita utilizes the best season for scyphistoma growth (August to September) and strobilates during the highest zooplankton abundance in October. C. capillata strobilates during the spring (March to May), and the abundance of C. capillata medusae is more dependent on immigration from the North Sea than A. aurita. C. lamarckii does not reproduce at all in the Gullmar Fjord and is totally dependent on immigration from the North Sea. The possibility of interspecific competition between A. aurita and C. capillata is discussed. A preliminary experiment showed that scyphistomae of A. aurita eat planula larvae of C. capillata during the autumn.     

Sexual reproduction of the scyphomedusa Aurelia aurita in relation to temperature and variable food supply

The effects of food availability and temperature on sexual maturation and female reproductive output of the scyphomedusa Aurelia aurita was examined in two populations from the contrasting environments of Southampton Water and Horsea Lake, England. Trends in oogenesis and subsequent reproductive output differed markedly between the two populations. In Southampton Water, the onset of sexual maturation occurred earliest in the larger medusae, but eventually all females became ripe, the smallest being 45 mm bell diameter (BD). The decrease in minimum size at maturity was correlated with increasing temperature. In A. aurita from Horsea Lake, size at maturity varied on a seasonal basis, with the smallest ripe female being only 19 to 20 mm BD. There were spring and autumn periods of sexual maturation in this population. During the autumn period, it is likely that food limitation was playing a more critical role in determining medusa size, with decreasing temperature indirectly affecting A. aurita by limiting primary and secondary production. In similar-sized ripe medusae, fecundity was greater in Southampton Water, but the planula larvae produced were significantly smaller than those in Horsea Lake. It is suggested that in Horsea Lake, the quality of the larvae are greater in terms of biochemical content to ensure survival of the few gametes produced (i.e. K-strategy). Comparison of the reproductive effort of the two A. aurita populations revealed that medusae from Southampton Water, which experience greater food availability, are able to direct more energy to reproduction than Horsea Lake medusae. In the latter, A. aurita medusae appear to partition the available food resources into either somatic growth (and therefore increased future fecundity) when food is abundant, or reproductive growth when food is scarce. Received: 24 June 1997 / Accepted: 23 March 1998     

Density-dependent effects control the reproductive strategy and population growth of <Emphasis Type="Italic">Aurelia</Emphasis><Emphasis Type="Italic">aurita</Emphasis> s.l. scyphistomae

Aureliaaurita s.l. scyphistomae are capable of developing different asexual modes for propagation and thus present a multi-mode reproductive strategy. The reproduction rates and the reproductive strategy they adopt depend on a combination of various environmental parameters. We investigated the A.aurita s.l. polyp-to-polyp reproduction strategy and population growth in relation to polyp density. Our results confirmed that density-dependent factors control population growth of A. aurita s.l. scyphistomae in three different ways: (1) decreasing the polyp reproduction rate, (2) triggering the production of motile bud-like tissue particles and (3) inducing the detachment of developed scyphistomae. Whereas the decrease in the reproduction rate reduces the number of recruits, the motile particles and the detachment of scyphistomae contribute to minimizing density-dependent effects by allowing reproductive products and scyphistomae to drift away. Thus, not only are the negative effects of intraspecific competition for space and food diminished but also the potential colonization of new substrates, and further increase in scyphistoma density is favoured on larger spatial scales. The potential capability to switch its polyp-to-polyp reproduction strategy in response to environmental clues and population density may give Aurelia high adaptability in the temperate coastal waters where they commonly live and where they may be exposed to wide-ranging and fluctuating environmental variables that affect their survival and longevity. Considering these features, as well as the wide tolerance of Aurelia scyphistomae (and medusae) to environmental parameters, it is not surprising that the species/lineages of Aurelia are cosmopolitan and exhibit the most frequent bloom events worldwide.     

Life cycle of the jellyfish <Emphasis Type="Italic">Rhizostoma pulmo</Emphasis> (Scyphozoa: Rhizostomeae) and its distribution,seasonality and inter-annual variability along the Catalan coast and the Mar Menor (Spain,NW Mediterranean)

Rhizostoma pulmo is one of the most abundant scyphomedusae along the Mediterranean coasts. To understand changes in the population densities of the medusa stage and its relationship with the benthic stage, we describe all developmental stages from the life cycle of R. pulmo, from the scyphistoma stage to young medusae reared in the laboratory. Mature scyphistomae showed a mean total body length of 1.7 mm and the average tentacle number was 16. Asexual reproduction occurred by lateral budding, podocyst and pedalocyst production. Each strobila released up to 8 ephyrae that had a mean total body diameter of 3.5 mm. Moreover, we also present data on the temporal and spatial distribution of the species in the Catalan Sea and the coastal lagoon on Mar Menor (NW Mediterranean) during the years 2007–2009. In the Catalan Sea, the presence of adult R. pulmo was recorded as extended along the whole coast, but most of the observation was concentrated in the central area; the highest abundances were recorded during the months of July and August. The highest number of observations was detected in 2008 in coincidence with the inter-annual variation observed in the Mar Menor lagoon.     

Feeding rates of the jellyfish Aurelia aurita on fish larvae

We quantified feeding rates of field caught Aurelia aurita feeding on yolk sac cod (Gadus morhua) larvae in a series of incubation experiments. A short-time (~1 h) functional response experiment with a wide range of prey concentrations (0.5–16 prey l⁻¹, initial concentration) revealed that ingestion rates increased linearly over this range, such that clearance rates were similar between the different prey concentrations. This suggests that A. aurita is capable of efficiently utilizing dense prey patches. This indication was further supported by a linear increase of prey captured by A. aurita during 2.5 h of feeding at extremely high prey concentration (>200 prey l⁻¹). Clearance rate in darkness scaled with jellyfish diameter to a power of ~1.7 for jellyfish 3.9–9.5 cm in diameter. The jellyfish did not alter their umbrella pulse frequency in response to presence of fish larvae. There were no significant differences between A. aurita feeding rates in light and darkness for yolk sac prey ages 0–7 days (at 7.5°C). Although prey vision and escape abilities of fish may develop rapidly during early larval ontogeny, these factors apparently have little impact on interactions with predators such as A. aurita during the yolk sac stage.     

Distribution and abundance of moon jellyfish (Aurelia aurita) and its zooplankton food in the Black Sea

The distribution of moon jellyfish (Aurelia aurita Linnaeus, 1758) in the Black Sea was determined from plankton samples collected above the anoxic zone (maximum depth 200 m) in the summer, winter and spring during 1991–1995. Distribution was patchy. Average biomass ranged from 98 to 380 g m⁻², and abundance varied from 2 to 14 individuals m⁻². Biomass and abundance peaked in late spring and summer. The distribution was correlated with hydrographic features in the Black Sea, with higher concentrations occurring at the peripheries of anticyclonic eddies. Centers of the two main cyclonic gyres generally had a low biomass of A. aurita. From July 1992 to March 1995, the populations were largely concentrated in offshore regions. A. aurita were confined to the upper part of the mixed layer. Smaller A. aurita (≤1 cm) were present in early spring (March), and individuals reached maximum size in the summer. Release of the epyhrae occurred in spring on the northwestern shelf of the sea when the seawater temperature was 11–12 °C. Microscopic analysis of stomach contents showed that copepods and mollusks form their main diet. Received: 3 September 2000 / Accepted: 29 September 2000     

Seasonal development of scyphozoan medusae and the predatory impact of Aurelia aurita on the zooplankton community in the Bornholm Basin (central Baltic Sea)

The annual cycle of abundance and distribution of the scyphozoan medusae Aurelia aurita and Cyanea capillata was studied in the Bornholm Basin (central Baltic Sea) in 2002. Seasonal changes in prey composition and predatory impact were investigated by analyzing stomach contents. A. aurita occurred from July to November, with a maximum mean abundance of 2.3 ind. per 100 m³ in August, whereas C. capillata was caught in much smaller numbers from July to September. No ephyrae of either species were found; therefore, advection of medusae from the western Baltic Sea is assumed. From July to October, ~80% of A. aurita medusae was distributed in the upper 20 m above the thermocline, whereas C. capillata occurred only in the halocline below 45 m. A. aurita did not migrate vertically and fed mainly on the most abundant cladoceran species Bosmina coregoni maritima. Further prey organisms were the cladocerans Evadne nordmanni and Podon spp., mollusk larvae and copepods. Copepod nauplii and copepodite stages I–III were not eaten by the medusae, neither were fish eggs and larvae used as prey. Based on mean medusa and zooplankton abundance from the upper 20 m, the predatory impact was very low. In August, when mean abundance of A. aurita was highest, only 0.1% of the copepod and 0.5% of the cladoceran standing stock were eaten per day. However, in regions with higher medusa or lower zooplankton abundance, up to 7.9% of the cladoceran standing stock was consumed per day. Hence, A. aurita did not regulate the zooplankton community in the Bornholm Basin, and fish larvae did not suffer from competition with and predation by the medusae.Communicated by O. Kinne, Oldendorf/Luhe     

Release of dissolved organic carbon (DOC) by the scyphozoan jellyfish Aurelia aurita and its potential influence on the production of planktic bacteria

A series of incubation experiments were made to measure the rate of release of dissolved organic carbon (DOC) by the jellyfish Aurelia aurita (L.) (collected in 1991–1992 in Gullmarsfjorden, Sweden). Release of DOC by medusae (9.5 to 18 cm in diameter) from the Skagerrak ranged from 0.70 to 1.6 mg C ind^-1 d^-1 with a mean of 1.2 mg C ind^-1 d^-1 (SD=0.29 mg C ind^-1 d^-1, n=10). Based on data from the literature for two medusa populations, this can be equivalent to 2.5 and 7.1% of the carbon assimilated in one season (June to September). This was similar to the amount of carbon allocated to reproduction. Bacterial abundance was monitored to evaluate the possible stimulating effect of the DOC released. Bacterial growth was stimulated by the presence of A. aurita. The importance of A. aurita as a source of DOC on a large scale is small compared to exudate from primary producers. The volume surrounding each medusa, wherein the DOC released may be enough to sustain a bacterial production such as the one reported from the Swedish west coast, is equivalent to a sphere with a diameter of 0.5 m. Thus, considering the patchy distribution of medusae, the local influence of their DOC release could be important.     

Potential dietary effects on the fatty acid composition of the common jellyfish Aurelia aurita

Fatty acid composition of the natural and aquarium-reared common jellyfish Aurelia aurita was investigated. Fatty acid composition of the aquarium-reared A. aurita clearly reflected that of the diet, brine shrimp (Artemia). In the same way, fatty acid composition of the natural A. aurita was assumed to reflect those of natural diets. Samples of natural A. aurita were collected from April 1995 to September 1995 in the Seto Inland Sea, Japan, and their fatty acids were analyzed by gas chromatography and mass spectrometry. Variation of fatty acid compositions was seasonal rather than dependent on body size. Two major seasonal groups were divided by the cluster analysis of the A. aurita fatty acid composition: the April–June and the August–September clusters. The April–June cluster was characterized by high contents of the (n − 3)-fatty acids of diatom origin, accumulated via the grazing food chain. By contrast, the August–September cluster was characterized by an increase in (n − 6)-fatty acids of macroalgal origin, probably transferred via the detritus food chain. These results suggest that the diet of natural A. aurita may shift between the diatom-based food chain and the detritus-based food chain. Received: 12 April 2000 / Accepted: 1 December 2000     

Recent distribution and size structure of gelatinous organisms in the southern Black Sea and their interactions with fish catches

The spatial distributions of gelatinous organism were studied during three cruises in 2006–2007. These were the first such studies conducted in the southern Black Sea for last decade. Additionally, the different methods of estimating gelatinous organism biomass presently in use were compared and recent situation of pelagic fishery interacting with zooplankton in the Black Sea were overviewed. Biomasses and abundances of both invading Mnemiopsis leidyi, and the resident Aurelia aurita and Pleurobrachia pileus were remarkably reduced (total gelatinous biomass: 417–537 g m⁻² in May, June, and 150 g m⁻² in October) as compared with those before the 1997 with invasion Beroe ovata in the southern Black Sea. Specimens of B. ovata were detected only in October when individuals with lengths of 10–50 mm comprised 93% of its population. Length–weight based biomasses were significantly variable for all species depending on the size structure in time. Larger sized individuals (>30 mm) of M. leidyi appeared as compared with those before year 1997. The ecosystem of the Black Sea has been suppressed both bottom–up through decreased eutrophication and top–down through reduced grazing on mesozooplankton by M. leidyi that are in turn controlled by grazing by B. ovata. The catch of anchovy was abruptly reduced to 120,000 tons due presumably to the considerably increased catch of its predator, the bonito (64,000 tons) in the year 2005.     

Intraguild predatory interactions between the jellyfish <Emphasis Type="Italic">Cyanea capillata</Emphasis> and <Emphasis Type="Italic">Aurelia aurita</Emphasis>

While qualitative observations of jellyfish intraguild predation abound in the literature, there are only few rate measurements of these interactions. We quantified predation rates among two common jellyfish in northern boreal waters, Cyanea capillata and its prey Aurelia aurita, both of which also feed on crustacean zooplankton and fish larvae. A series of incubation experiments using a wide range of prey concentrations (0.38–3.8 m⁻³) in large containers (2.6 m³) was carried out. By replenishing the prey continuously as they were captured we maintained a nearly constant prey concentrations. Ingestion rates increased linearly up to prey concentrations of 1.92 m⁻³, yielding maximum clearance rates of ∼2.37 ± 0.39 m³ predator⁻¹ h⁻¹ for C. capillata predators 16 ± 2.3 cm in diameter. Mean ingestion rate at saturated prey concentrations (1.92–3.85 m⁻³) was 4.01 ± 0.78 prey predator⁻¹ h⁻¹. Behavioral observations suggested that predators did not alter their swimming behavior during meals, and thus that feeding rates were generally handling limited rather than encounter limited. Predators captured more prey than needed, and semi-digested prey was often discarded when fresh prey was encountered.     

Nucleic acid and protein levels in strobilating polyps of Chrysaora quinquecirrha and Aurelia aurita

Levels of DNA, RNA, and protein were measured in scyphistomae of the scyphozoans Aurelia aurita and Chrysaora quinquecirrha during strobilation. In synchronously developing populations of A. aurita, the amount of DNA per polyp increases 41 to 260% during strobilation, whereas RNA and protein remain relatively constant. The RNA/DNA ratio drops by about 50% during strobilation in both C. quinquecirrha and A. aurita, and protein/DNA decreases by 50% in A. aurita. Specific RNA reserves are probably not accumulated in advance of strobilation, since strobilation is blocked immediately in both species by 1 to 3 g/ml actinomycin D. The size and DNA content of polyps are usually increased by prolonged incubation at temperatures of 12° to 15°C, which facilitates strobilation; however, the RNA/DNA and protein/DNA ratios of such polyps are not significantly increased by the cold conditioning.Contribution No. 472 from the Virginia Institute of Marine Science.     

Prey selection by the scyphomedusan predator Aurelia aurita

We describe feeding behavior of Aurelia aurita (Linnaeus) using gut content analyses of field-collected specimens and a mesocosm experiment. The field studies were conducted in Narragansett Bay, Rhode Island, USA from March to April 1988, and the mesocosm studies were done at the Marine Ecosystems Research Laboratory at the University of Rhode Island. Patterns of prey selection changed with medusa diameter. Smaller medusae (12 mm diameter) consumed mostly hydromedusan prey whereas larger medusae (up to 30 mm diameter) ingested greater numbers of copepod prey. While larger medusae did feed on copepods, their diet also contained more barnacle nauplii and hydromedusae than expected from the relative abundances of these prey types in plankton samples. A marginal flow mechanism of feeding by A. aurita provided an explanation for the patterns of prey selection we observed in medusae of different sizes and among widely divergent prey types. Our data indicated that large prey, with escape speeds slower than the marginal flow velocities around the bell margins of A. aurita, made up a substantial fraction of the daily ration when they were available. Such prey species may be more important to nutrition than the more abundant copepods and microzooplankton. Successful development of young medusae may depend upon an adequate supply of slowly escaping prey.     

Population dynamics,reproduction and growth of the Indo-Pacific horned sea star, <Emphasis Type="Italic">Protoreaster nodosus</Emphasis> (Echinodermata; Asteroidea)

The horned sea star (Protoreaster nodosus) is relatively common in the Indo-Pacific region, but there is little information about its biology. This study of the population biology of P. nodosus was carried out in Davao Gulf, The Philippines (7°5′N, 125°45′E) between September 2006 and May 2008. Protoreaster nodosus was found in sand and seagrass dominated habitats at a mean density of 29 specimens per 100 m² and a mean biomass of 7.4 kg per 100 m², whereas a significantly lower density and biomass was found in coral and rock dominated habitats. Adult specimens (mean radius R = 10.0 cm) were found at depths of 0–37 m, whereas juveniles (R < 8 cm) were only found in shallow sandy habitats with abundant seagrass (water depth ≤2 m). Increased gonad weights were found from March to May (spawning period), which coincided with an increasing water temperature and a decreasing salinity. Density and biomass did not change significantly during reproduction, but sea stars avoided intertidal habitats. All specimens with R > 8 cm had well developed gonads and their sex ratio was 1:1. Protoreaster nodosus grew relatively slowly in an enclosure as described by the exponential function G = 7.433 e^{−0.257 × R} . Maturing specimens (R = 6–8 cm) were estimated to have an age of 2–3 years. Specimens with a radius of 10 cm (population mean) were calculated to have an age of 5–6 years, while the maximum age (R = 14 cm) was estimated as 17 years. Potential effects of ornamental collection on the sea star populations are discussed. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Seasonal patterns in size and abundance of <Emphasis Type="Italic">Phyllorhiza punctata</Emphasis>: an invasive scyphomedusa in coastal Georgia (USA)

Phyllorhiza punctata, commonly called the Australian white spotted jellyfish, invaded the Caribbean in the 1960s, becoming established there and subsequently in the United States in the northern Gulf of Mexico (by 2000) and eastern Florida (2001). With the prevailing Loop Current flowing clockwise around the Gulf of Mexico and joining the Gulf Stream along eastern Florida, potential transport of P. punctata along the eastern seaboard of the USA could be facilitated. P. punctata medusae were collected in small numbers along the entire Georgia coast during May–November in 2007 and 2008. Medusa bell diameters increased both years from ca. 10 cm in May to ca. 33 cm in autumn. Specimens lacked zooxanthellae, as reported for medusae in the northern Gulf of Mexico and Florida. It is possible that the P. punctata medusae observed were transported from established populations to the south; however, whether or not this species is established along the Georgia coast has yet to be determined.     

Feeding of Clausocalanids (Calanoida,Copepoda) on naturally occurring particles in the northern Gulf of Aqaba (Red Sea)

A total of 12 feeding experiments were conducted in the northern Gulf of Aqaba during spring (March/April) and autumn (September/October) 2002 at the Marine Science Station (MSS) in Aqaba. Females of three species of clausocalanids were selected: Clausocalanus farrani, C. furcatus and Ctenocalanus vanus. Natural occurring particle (NOP) larger than 5 μm were investigated as food source. The ambient chlorophyll a concentration at sampling depth (∼70 m) ranged between 0.15 and 1.00 μg chl a l⁻¹ and NOP concentrations ranged between 1.78 and 14.0 × 10³ cells l⁻¹ during the sampling periods. The division of particles into five size classes (5–10, 10–20, 20–50, 50–100 and >100 μm) revealed that most of the particles were found in the size classes below 50 μm (81–98%), while most of the natural occurring carbon (NOC) was concentrated in the size classes larger than 20 μm (70–95%). Ingestion rates were food density dependent rather than size dependent ranging between 0.02 and 1.65 × 10³ NOP ind⁻¹ day⁻¹ and 0.01 and 0.41 μg NOC ind⁻¹ day⁻¹, respectively, equivalent to a body carbon (BC) uptake between 0.4 and 51.8% BC day⁻¹. The share of the size classes to the total ingestion resembled in most cases the size class composition of the natural particle community.     

Swimming ability of eels (<Emphasis Type="Italic">Anguilla rostrata,Conger oceanicus</Emphasis>) at estuarine ingress: contrasting patterns of cross-shelf transport?

The transport of eel early life stages may be critical to their population dynamics. This transport from ocean spawning to freshwater, estuarine and coastal nursery areas is a combination of physical and biological processes (including swimming behavior). In New Jersey, USA, the American eel (Anguilla rostrata) enters estuaries as glass eels (48.7–68.1 mm TL) in contrast to the Conger eel (Conger oceanicus) that enters as larger (metamorphosing) leptocephali (68.3–117.8 mm TL). To begin to understand the mechanisms of cross-shelf transport for these species, we measured the potential swimming capability (critical swimming speed, U _crit) under ambient conditions throughout the ingress season. A. rostrata glass eels were collected over many months (January–June) at a range of temperatures (4–21°C), with relative condition declining over the course of the ingress period as temperatures warmed. C. oceanicus occurred later in the season (April–June) and at warmer temperatures (14–24.5°C). Mean U _crit values for A. rostrata (11.7–13.3 cm s⁻¹) and C. oceanicus (14.7–18.6 cm s⁻¹) were comparable, but variable, with portions of the variability explained by water temperature, relative condition, ontogenetic stage, and fish length. Travel times to Little Egg Inlet, New Jersey, estimated using 50% U _crit values, indicate it would take A. rostrata ~30 and ~60 days to swim from the shelf edge and Gulf Stream, respectively. Travel times for C. oceanicus were shorter, ~20 days from the shelf edge, and ~45 days from the Gulf Stream. Despite differences in life stage, our results indicate both species are competent swimmers, and suggest they are capable of swimming from the Gulf Stream and/or edge of the continental shelf to estuarine inlets.