Using the empirical Bayes method to estimate and evaluate bycatch rates of seabirds from individual fishing vessels

Minimizing bycatch of seabirds is a major goal of the U.S. National Marine Fisheries Service. In Alaska waters, the bycatch (i.e., inadvertent catches) of seabirds has been an incidental result of demersal groundfish longline fishery operations. Notably, the endangered short-tailed albatross (Phoebastria albatrus) has been taken in this groundfish fishery. Bycatch rates of seabirds from individual vessels may be of particular interest because vessels with high bycatch rates may not be functioning effectively with seabird avoidance gears, and there may be a need for suggestions on how to use these avoidance gears more effectively. Therefore, bycatch estimates are usually made on an individual vessel basis and then summed to obtain the total estimate for the entire fleet.

Interactions between marine mammals and pelagic longline fishing gear in the U.S. Atlantic Ocean between 1992 and 2004

The U.S. East Coast pelagic longline fishery has a history of interactions with marine mammals, where animals are hooked and entangled in longline gear. Pilot whales (Globicephala spp.) and Risso’s dolphin (Grampus griseus) are the primary species that interact with longline gear. Logistic regression was used to assess the environmental and gear characteristics that influence interaction rates. Pilot whale inter-actions were correlated with warm water temperatures, proximity to the shelf break, mainline lengths greater than 20 nautical miles, and damage to swordfish catch. Similarly, Risso’s dolphin interactions were correlated with geographic location, proximity the shelf break, the length of the mainline, and bait type. The incidental bycatch of marine mammals is likely associated with depredation of the commercial catch and is increased by the overlap between marine mammal and target species habitats. Altering gear characteristics and fishery practices may mitigate incidental bycatch and reduce economic losses due to depredation.

Biological characteristics and mortality of western butterfish (Pentapodus vitta), an abundant bycatch species of prawn trawling and recreational fishing in a large subtropical embayment

The western butterfish (Pentapodus vitta) is numerous in the bycatch of prawn trawling and recreational fishing in Shark Bay, Western Australia. We have thus determined crucial aspects of its biological characteristics and the potential impact of fishing on its abundance within this large subtropical marine embayment. Although both sexes attained a maximum age of 8 years, males grow more rapidly and to a larger size. Maturity is attained at the end of the first year of life and spawning occurs between October and January. The use of a Bayesian approach to combine independent estimates for total mortality, Z, and natural mortality, M, yielded slightly higher point estimates for Z than M. This result indicates that P. vitta is lightly impacted by fishing. It is relevant that, potentially, the individuals can spawn twice before recruitment into the fishery and that 73% of recreationally caught individuals are returned live to the water.

A history of fishing with explosives and poisons in Hong Kong waters

Fishing with explosives is still being practiced aroung Hong Kong. The first legislation against blast fishing was passed in Hong Kong in 1903. Since then, successive legislation has increased the penalties and fines on blast fishing and fishing with poisons. However, the problem has not been eliminated as enforcement puts pressure on the resources of the marine police. It would be more effective to educate the local communities on the destructive effects of these practices and make them more vigilant and responsible in controlling them.

Diversity of selective and non-selective fishing gear and their impact on inland fisheries in Bangladesh

The paper describes the wide range of traditional fishing gear used by subsistence and professional fishers in the inland waters in Bangladesh as well as their impact on the fisheries and the environment. The negative impacts indicate the need for regulation of specific types of fishing gear at particular times of the year. An awareness/training program should be extended to the fishermen to create awareness of the long-term effects of their fishing practices and to impart knowledge of fishing laws.

Relationship between sea surface temperatures and dolphin-associated fishing activities by the Mexican tuna fleet

Data from the Mexican purse seiner fleet operating in the eastern Tropical Pacific, for the year 1985-1990, are used to show that the fraction of surface schools of yellowfin tuna Thunnus albacares associated with dolphins (Stenella attenuata and others) increases with sea surface temperature. Possible reasons for this correlation are briefly discussed.

Assessment of the fishing effort level in the shrimp fisheries of the central and southern Gulf of California

In view of the concern caused by the declining trend in the annual shrimp yield in the Central Gulf of California, an attempt was made to analyze the fishing effort level exerted upon the shrimp stocks of the blue (Farfantepenaeus stylirostris) and the brown shrimp (F. californiensis) from 1980 to 1991. For this purpose, both Schaefer and Fox production models were applied. The results from these analyses revealed an economic overexploitation condition, and suggested an imperative need to implement as a regulatory measure, the reduction of the catch per unit of effort level (CPUE) to keep the fishery within acceptable bioeconomic margins of a maximum sustainable yield (Ys). This can only be achieved through the adjustment of the fleet size from 481 vessels down to 250 or 275.

VPA estimates of fishing mortality and exploited biomass from Sardinella aurita catch-at-length data in eastern Venezuela

In this study, length-frequency data on Spanish sardine (Sardinella aurita) from northeastern Venezuela were analyzed for the period 1967-1989. Average growth parameters for the von Bertalanffy equation were established as L sub( infinity )= 26.6 cm (TL) and K = 1.26 year super(-1). The number of recruits to the fishing area, estimated from length-structured Virtual Population Analysis, varied from <10 super(8) in the late 1960s to >10 super(9) at the end of the 1980s. Exploited biomass estimates for the same period varied from less than 20,000 t in the first year to more than 100,000 in 1989. Both recruitment and exploited biomass showed different seasonal patterns between 1976-1983 and 1984-1988. Despite some uncertainty regarding these estimates, it is considered that major population tendencies are adequately represented by this analysis

Blast fishing in southwest Sulawesi, Indonesia

Blast fishing has been a widespread and accepted fishing technique in Indonesia for over 50 years. The largest coral reef fishery in Indonesia is around the Spermonde archipelago in southwest Sulawesi. With the expanding population and the increasing demand for fish for export, fishing has intensified and fish catches per unit effort are stable or declining. The use of bombs made with a mixture of kerosene and fertilizer is widely prevalent. In the market of the city of Ujung Pendang, an estimated 10-40% of the fish from capture fisheries are caught through blast fishing. This is destroying the hard corals. Blast fishing is seen by the fishers as being much easier and results in higher catches than with other traditional methods. They believe that the only way to limit this practice is with stricter policing and higher fines. An effective management option could be to establish national marine reserves within the archipelago, supported by other income-generating activities.

Estimating input demand and output supply elasticities in gillnet and seine fishing in Guimaras Strait and adjacent waters

This contribution is a summary of the results of the study conducted by the University of the Philippines in the Visayas team from November 1990 to June 1991. The purpose of this research is to estimate demand and output supply elasticities in gillnet and seine fishing in Guimaras Strait (Philippines) and adjacent waters.

Padal fishing - a unique fishing method in the Ashtamudi Estuary of Kerala (south India)

Bush park fishing / padal fishing is an indigenous fishing method widely employed in the Ashtamudi estuary of Kerala (south India). An artificial reef made from twigs and leaves of trees is planted in the shallow areas of the estuary. The aim is to harvest fish that find shelter in these structures for the purpose of feeding and breeding. Though the State Department of Fisheries has banned this method of fishing in the inland waters of Kerala, 400 padals are operating in this estuary. About 300 of them are anchored in the western parts of the estuary (west Kayal). Fish are harvested in the padals at monthly intervals almost round the year and this results in the destruction of a sizeable quantity of juveniles and sub-adults of the commercially important fishes, such as Pearl spot and mullets, from the estuary. These padals pose a major threat to the sustainability of the fishery resources of this estuary and, therefore, need to be phased out by providing alternative occupations for the fishermen who are dependant on the padals.

Brush shelter: a recently introduced fishing method in the Kaptai reservoir fisheries in Bangladesh

This paper describes the brush shelters in Kaptai Lake based on a field survey of four major fishing grounds undertaken in Jan-Dec 1997.

Dynamite fishing in Sierra Leone

The dynamite fishing operations in Sierra Leone are enumerated and discussed.

Community-based coastal resource management in Orion (Bataan, Philippines) : building community property rights in a fishing community

The Community-based Coastal Resource Management Project in Orion, Bataan, Philippines was started in 1991. The village level fishers organizations have formed a municipal-wide association called the Samahan at Ugnayan ng Pangisdaan sa Orion (SUGPO). It represents 70% of the small-scale fishers in Orion and has taken on the task of rehabilitating the degraded fishing grounds. The experience in Orion indicates that coastal resource management can be successful if the fishers have ownership of the program and the costs and benefits of the program are distributed equally in a manner acceptable to them.

Who's working on fishing gear design and construction for small-scale fisheries?

The findings are presented of a search conducted on traditional fishing gear design and construction using the ASFA database (1971-90) and the ICLARM Library and professional staff collections.