Total Factor Productivity Change in the New England Groundfish Fishery: 1964–1993

We develop estimates of total factor productivity (TFP) change in the New England groundfish fishery from 1964 to 1993, using a procedure similar to Squires' (1992, Rand J. Econom.23(2), 221–236) method, which extends standard TFP measurement by including the effect of fluctuations in stock abundance. The results indicate that TFP increased on average by 4.4% per year from 1964 to 1993. A higher average rate of increase occurred between 1964 and 1982, possibly due to new technologies (e.g., fishfinders). TFP declined at 0.33% annually from 1983 to 1993 due to stringent output and effort control measures.     

Understanding the sources and effects of abandoned,lost, and discarded fishing gear on marine turtles in northern Australia

Globally, 6.4 million tons of fishing gear are lost in the oceans annually. This gear (i.e., ghost nets), whether accidently lost, abandoned, or deliberately discarded, threatens marine wildlife as it drifts with prevailing currents and continues to entangle marine organisms indiscriminately. Northern Australia has some of the highest densities of ghost nets in the world, with up to 3 tons washing ashore per kilometer of shoreline annually. This region supports globally significant populations of internationally threatened marine fauna, including 6 of the 7 extant marine turtles. We examined the threat ghost nets pose to marine turtles and assessed whether nets associated with particular fisheries are linked with turtle entanglement by analyzing the capture rates of turtles and potential source fisheries from nearly 9000 nets found on Australia's northern coast. Nets with relatively larger mesh and smaller twine sizes (e.g., pelagic drift nets) had the highest probability of entanglement for marine turtles. Net size was important; larger nets appeared to attract turtles, which further increased their catch rates. Our results point to issues with trawl and drift‐net fisheries, the former due to the large number of nets and fragments found and the latter due to the very high catch rates resulting from the net design. Catch rates for fine‐mesh gill nets can reach as high as 4 turtles/100 m of net length. We estimated that the total number of turtles caught by the 8690 ghost nets we sampled was between 4866 and 14,600, assuming nets drift for 1 year. Ghost nets continue to accumulate on Australia's northern shore due to both legal and illegal fishing; over 13,000 nets have been removed since 2005. This is an important and ongoing transboundary threat to biodiversity in the region that requires attention from the countries surrounding the Arafura and Timor Seas. Entender las Fuentes y Efectos de Equipo de Pesca Abandonado, Perdido y Desechado sobre las Tortugas Marinas del Atlántico Norte     

Species Extinction in the Marine Environment: Tasmania as a Regional Example of Overlooked Losses in Biodiversity

Abstract:  We used Tasmania as a case example to question the consensus that few marine species have recently become extinct or are approaching extinction. Threats to marine and estuarine species—primarily in the form of climate change, invasive species, fishing, and catchment discharges—are accelerating, fully encompass species ranges, and are of sufficient magnitude to cause extinction. Our ignorance of declining biodiversity in the marine environment largely results from an almost complete lack of systematic broad-scale sampling and an overreliance on physicochemical data to monitor environmental trends. Population declines for marine species approaching extinction will generally go unnoticed because of the hidden nature of their environment and lack of quantitative data.     

Fishing sustainability via inclusion of man in predator-prey models: A case study in Lago Preto, Manacapuru, Amazonas

We modeled a fishery's system with two types of fishermen, commercial and subsistence fishermen, who exploit the fish stock at the Amazonian floodplain lakes. In the first model, we combined the Lotka-Volterra equations with Verhulst's Logistic model, by inserting hydrological cycle oscillations. The second model was based on the equations proposed by Berryman, which reflect the predator's functional response in relation to the prey's population behavior, taking into account the hydrological cycle. In both models, commercial fishermen and local direct consumers (called riverside dwellers - riverines - in the model), were considered the only predators acting upon fishing stocks. Primary data were collected in 48 riverside homes throughout 2006. The total number of interviewees corresponds to 69.6% of the universe of homes in the community defined as study area. The riverines were the predators that showed capacity to eliminate the opponent predators (commercial fishermen). The best scenery obtained regarding the number of prey, was the one that showed only commercial fishermen in the region. On the other hand, the simulations show that the coexistence is possible among predators, and between predators and their prey. The seasonal model with functional response provides a better response in relation to the system's current situation and to the established modeling conditions than the Lotka-Volterra seasonal model. The seasonal model with functional response also showed a better response pattern in all scenarios, with oscillations taking place more gradually, both for variations associated with the flooding pulse and for relations between predators and prey.     

Transaction of Marine Fishing Right: Theoretical Analysis

Abstract

The difference between fishermen’s fishing catch and the optimal fishing catch is the basic reason for the transaction of marine fishing rights (TMFR). The effects of productive cost, non-productive cost, use-cost, transaction cost, productive revenue and non-productive revenue on the TMFR and the optimal fishing catch are analyzed. This paper draws following conclusions: the non-productive revenue has a positive effect on the TMFR, and other factors, such as non-productive cost, use-cost and transaction cost, have a negative effect; the TMFR will promote the resource allocation; the high transaction cost may affect the implementation of TMFR.     

Not drowning, waving!: Safety management and occupational culture in an Australian commercial fishing port

An ethnographic study of safety management was conducted in a commercial lobster fishing industry, in a small fishing town in Southern Australia. The objectives were to test the utility of the ethnographic method for exploring the nature of the relationship between occupational culture, workplace social organization, and safety management.Available accident data suggests this particular fishery may not have the same high incidence of occupational trauma normally attributed to commercial fishing. Changes in licensing laws and improved management of fish stocks have significantly reduced risk exposure. Participants in this study had a good understanding of their physical workplace risks, but accepted some of these with too few defences. Wear rates of personal flotation devices (PFDs) were below 1% for the study period.The paper suggests that participants do not have a strong learning culture, and links this to occupation-wide cultural assumptions, other external issues and safety management issues. Assessment of the social and cultural context of safety management can offer policy makers a ‘road-map’ to guide their interventions. The utility of ethnographic methods for this type of analysis is significant, and will be enhanced by improving the transparency of the research method.     

FEE FISHING AREAS IN ILLINOIS1

ABSTRACT: Fishing is a popular form of recreation in the state of Illinois. Despite seemingly endless varieties of fishing opportunities, limited public access, distant location of lakes with respect to population centers, chemical contaminants in some waters, and the desire for species not naturally found in Illinois have engendered an alternate form of recreational land use, the daily fee fishing area. A fee area is any privately controlled body of water or waters where a fee is charged for fishing. Such operations must Low licensed by the state of Illinois. Fee areas are almost entirely comprised of existing man-made impoundments, particularly farm ponds. They are usually stocked on a put and take basis. The most common species utilized in Illinois are carp and channel catfish. Fee areas are concentrated in the southwestern part of the state and near major metropolitan centers. Even though the number of fee areas has declined during the past decade, the role of such operations remains important to the overall picture of fishing in Illinois.     

Acidification and recreational fisheries in Finland: A mail survey of potential impacts

In Finland, small forest lakes and rivers in the northern part of the country are more sensitive to acidic deposition than other Finnish waters. In some lakes, acid-sensitive fish populations have declined. A nationwide survey of fishers showed that, at present, the number of fishers whose primary fishing waters are affected by airborne acidification is negligible compared to the estimated total number of adult fishers (1.1 million). The proportion of the fishers who mainly fish in water types sensitive to airborne acidification is considerable, 3% for the rivers in northern Finland and 21% for small forest lakes. There is general concern among fishers about the effects of acidification. Changes in the fishing waters are attributed to acidification by 5–10% of the fishers, although in most cases other information about the fishing waters rules out acidification as an explanation for the changes. Among those who fish in sensitive types of waters, a willingness to mitigate potential damages was reported by approximately one third of all fishers. Clear differences in the willingness to rehabilitate the fishery were observed in relation to the importance of fishing as a spare time activity and the distance between the fishing waters and a home or summer cottage.     

长江上游干流春季禁渔前后三年渔获物结构和生物多样性分析

根据2000~2005年长江上游干流宜宾、巴南和万州3个江段三层流刺网的监测资料,分析了春禁前后3年渔获物结构和鱼类生物多样性的变化,对长江上游春禁效果进行了初步评价。春禁前后3年共监测到鱼类51种,隶属于3目18科（亚科）36属,以鲤科鱼类为主,占608%。春禁后,渔获物主要种类优势度有所下降,部分江段单位捕捞努力量渔获量表现出一定上升趋势,3个江段Margalef指数、Pielou指数和Wilhm改进指数有一定升高,表明种类丰富度有所提高,群落结构趋于复杂,春季禁渔有一定效果。春禁前后渔获物种类的波动,可能与这些种类种群数量少,难以采到有关;春禁后主要种类平均体长、体重仍表现出下降趋势,可能与过度捕捞及资源在短期内难以恢复有关。建议延长禁渔期、严格控制禁渔结束后的捕捞强度等措施来提高禁渔效果,并采取恢复江湖联系、保护重要渔业水域水质、实施水利工程生态调度等措施来配合春禁制度的实施。长江渔业资源的恢复和保护是一个长期而复杂的过程,对长江禁渔效果的准确评估还需要长期监测和深入研究。