Conservation Biology of Elasmobranchs

Elasmobranchs are vital and valuable components of the marine biota. From an ecological perspective they occupy the role of top predators within marine food webs, providing a regulatory control that helps balance the ecosystem. From an evolutionary perspective, this group represents an early divergence along the vertebrate line that produced many unusual, but highly successful, adaptations in function and form. From man's perspective, elasmobranchs have been considered both an unavoidable nuisance, and an exploitable fishery resource. A few of the large shark species have earned a dubious notoriety because of sporadic attacks on humans that occur in coastal areas each year worldwide; the hysteria surrounding an encounter with a shark can be costly to the tourist industry. More importantly, elasmobranchs are often considered a detriment to commercial fishing operations; they cause significant economic damage to catches and fishing gear. On the other hand, consumer attitudes have changed concerning many previously unpopular food fishes, including elasmobranchs, and this group of fishes has been increasingly used by both recreational and commercial fishing interests. Many elasmobranchs have become a popular target of recreational fishermen for food and sport because of their abundance, size, and availability in coastal waters. Similarly, commercial fisheries for elasmobranchs have developed or expanded from an increased demand for elasmobranch food products. (PDF file contains 108 pages.)

Additions to a revision of the shark genus Carcharhinus: Synonymy of Aprionodon and Hypoprion, and description of a new species of Carcharhinus (Carcharhinidae)

Features of the valid nominal species of Aprionodon Gill (isodon Valenciennes) and Hypoprion Muller and Henle (hemiodon Valenciennes, macloti Muller and Henle, and signatus Poey), plus those of a previously unrecognized species here described as Carcharhinus leiodon n.sp., are examined and compared with those of Carcharhinus Blainville. Features studied include morphometrics, vertebral numbers and other vertebral characteristics, tooth numbers, color pattern, and some other aspects of external morphology. It is concluded that on these features C. leiodon n.sp. is entirely encompassed within the parameters of Carcharhinus, and that, although A. isodon, H. hemiodon, H. macloti, and H. signatus each extend the range of diversity of Carcharhinus in one or more features, A. isodon is not uniquely different from Carcharhinus, and there is no common pattern of difference between the three species of Hypoprion and Carcharhinus. Accordingly, and because the nature of the teeth of Aprionodon and Hypoprion has been found insufficient to warrant generic distinction from Carcharhinus, the genera Aprionodon and Hypoprion are synonymised with Carcharhinus. A diagnosis and description are given for each of the above species. The descriptions include measurements, counts, and line illustrations that show the whole shark in lateral view, underside of head, nostril, and teeth. The geographic distribution is summarized, as are also the meager biological data available on number of embryos, size at birth, size at sexual maturity, and maximum size. (PDF file contains 32 pages.)

Shark catches from selected fisheries off the U.S. East Coast

(PDF file contains 28 pages.)

Fishing Long-Fingered Bats (Myotis capaccinii) Prey Regularly upon Exotic Fish

7 p.

Fishing guidelines

In accordance with the recommendations of the Committee on Fisheries (COFI), FAO prepared the first draft of the technical guidelines in relation to Fishing Operations, which were submitted to the Technical Consultation on the Code of Conduct for Responsible Fishing, Rome, 26 September to 5 October 1994. The draft was prepared taking into account the Declaration of Cancún, Agenda 21 of United Nations Conference on Environment and Development (UNCED) and the Report of the Expert Consultation on Responsible Fishing Operations, Sidney, British Colombia, Canada, 6 -11 June 1994. Thereafter, the draft was revised taking into account, the negotiations at the UN Conference on Straddling Fish Stocks and Highly Migratory Fish Stocks, the elaboration of the Code as well as developments at the International Maritime Organization (IMO) with regard to the Protocol to the Torremolinos International Convention on Fishing Vessel Safety and the new International Convention on Training, Certification and Watchkeeping for Fishing Vessel Personnel, 1995. Technical Guidelines are given in support of the implementation of the Code in relation to fishing operations. These are addressed to States, international organizations, fisheries management bodies, owners, managers and charterers of fishing vessels as well as fishers and their organizations. Guidance is also given with respect to the general public. (PDF contains 93 pages)

A study of changes in fishing effort, abundance, and yield for yellowfin and skipjack tuna in the Eastern Tropical Pacific Ocean

ENGLISH: The rapid growth of the Eastern Pacific fishery for yellowfin and skipjack tuna since the end of World War II has given rise to questions concerning the rational utilization of these resources. As part of the Inter-American Tropical Tuna Commission's program of research designed to investigate these problems, a study was undertaken to determine from the historical records of the fishery the effects of fishing upon the stocks of yellowfin and skipjack tuna of the Eastern Pacific region and to evaluate the present condition of these stocks with respect to the maximum equilibrium yield. SPANISH: EI rápido crecimiento, desde la terminación de la Segunda Guerra Mundial, de la pesquería de atún aleta amarilla y barrilete en el Pacifico Oriental, ha dado lugar a que se hagan algunos comentarios sabre la racional utilización de estos recursos. Como parte del programa de la Comisión Interamericana del Atún Tropical designado para la investigación de estos problemas, un estudio fué llevado a cabo para determinar, de los informes historicós de la pesquería, los efectos de la pesca sobre los stocks de atún aleta amarilla y barrilete de la región del Pacifico Oriental y para evaluar la presente condición de estos stocks con respecto al máximo rendimiento de equilibria. (PDF contains 123 pages.)

Measures of tuna abundance from purse-seine operations in the Eastern Pacific Ocean, adjusted for fleet-wide evolution of increased fishing power, 1960-1971

ENGLISH: The fishing power of the tuna purse-seine fleet of the eastern Pacific Ocean has increased since the early 1960's. Because the entire fleet seems to have adopted equipment and techniques to increase its efficiency in capturing tunas, traditional methods of adjusting catch rates to a reference vessel type of fixed efficiency to index tuna abundance from fishing success are inapplicable. Instead, a methodology for such adjustment based on a mathematical representation of purse seining activities is developed. Observed changes in efficiency in subprocesses of purse seining are then used to adjust catch rates when computing abundance histories for yellowfin and skipjack in large regions of the eastern Pacific Ocean. SPANISH: La eficacia de pesca de la flota de cerco atunera en el Océano Pacífico oriental ha aumentado desde el comienzo del decenio de 1960. Como toda la flota parece haber adoptado equipo y métodos para incrementar su eficaciaen capturar atunes, no se pueden aplicar los métodos tradicionales de ajustar los índices de captura a un tipo normalizado de barco (es decir de eficacia fija) para indicar la abundancia del atún según los resultados de pesca. En su lugar se ha desarrollado un método para realizar tal ajuste basado en una representación matemática de las actividades de las embarcaciones de cerco. Cuando se calcula la abundancia histórica del atún aleta amarilla y barrilete en grandes regiones del Océano Pacífico oriental, se usan entonces los cambios observados en la eficacia de los subprocesos cerqueros para ajustar los índices de captura. (PDF contains 120 pages.)

Trawling gear and towing power of the Nigerian inshore fishing trawlers

This paper deals with the relation between trawling gear and towing power of the Nigerian inshore fishing trawlers. Information on the size as well as weight variations of the existing otter boards as they relate to the horse power of the engine and length of warps in relation to fishing depth are given

A synopsis of the traditional fishing gears used in artisanal fisheries along the upper part of the Cross River

Artisanal fishery is the main type of fishing practised occupationally by the fishermen along the upper sectors of the Cross River. No form of mechanised fishing has so far been introduced to the fishermen in these areas. This study has attempted to find out the different gears used, when and where used along the main river channel, its tributaries and flood plains. An effort has also been made to provide some information on the types of fishes caught with the different gears. Recommendation for effective management are also advanced

A review of manpower training for Nigeria's fishing industry

An examination is made of the organization and administration of fisheries training institutes in Nigeria, highlighting their inadequacies in achieving required goals. A systems approach to fisheries manpower training is described which is based on 4 principles: 1) wholeness; 2) systematization; 3) compatibility; and 4) optimization

Relevance of the programmes of the federal fisheries schools to Nigeria's fishing industry

Nigeria's three federal fisheries schools are administered by three autonomous research institutes located in Lagos, New Bussa, and Maiduguri. The schools were established at different periods to train the required manpower for Nigeria's fishing industry which has remained predominantly artisanal since its inception in 1942 as a Second World War exigency. Despite the establishment of the schools, the industry's manpower is still being dominated by non-nationals especially in the capture fisheries sub-sector. The common features of the schools include the apparent insensitivity of their programmes to the industry's dynamic manpower needs; the absence of coordination of their programmes by a national body which would have ensured that the schools are able to communicate with one another and are willing to act and share a purpose. The need and the methodology for a change of emphasis from the on-going training of extension agents and officers to that of fishing operatives and technicians to enable Nigeria effectively harness her local fish resources towards self-sufficiency is highlighted.

The Siem Reap Meet Proceedings: Asserting Rights, Defining Responsibilities: Perspectives from Small-scale Fishing Communities on Coastal and Fisheries Management in Asia

This publication is a record of the proceedings of the Siem Reap Workshop and Symposium. It provides a bottom-up perspective on how rights are understood, and what rights are seen as important by small-scale fishing communities, if they are to fulfil their responsibilities for managing resources in a sustainable and equitable manner. It is hoped that these proceedings, and the Statement from the Workshop-the Siem Reap Statement-are found useful by those engaged in policy making and advocacy in support of small-scale fisheries, as well as researchers, non-governmental organizations (NGOs), fishworker organizations, and multilateral and regional organizations

The Zanzibar Workshop Proceedings: Asserting Rights, Defining Responsibilities:Perspectives from Small-scale Fishing Communities on Coastal and Fisheries Management in Eastern and Southern Africa

The Zanzibar Workshop Proceedings consists of the report and the Statement of the Workshop and provides a rich understanding of the dynamics of traditional, indigenous, small-scale and artisanal fisheries and fishing communities in the Eastern and Southern African (ESA) context. The issues covered include: the saga of rights denied to coastal lands, fishing, and threats to livelihood arising from lack of recognition of traditional rights and the livelihood needs of people in the region; the aspirations of coastal and inland communities to maintain or improve their livelihoods; and a bottom-up perspective on access rights to fishing, post-harvest rights and economic and social rights. This report will be a valuable source of information for community organizers, trade union leaders, government officials and the donor community, including multilateral organizations, researchers and for all those who are interested in the well-being of ESA fishing communities.

Trace metals -- a potential threat to our fishing industry

Trace metals constitute a major form of water pollutant that can adversely affect fish production. The potentially toxic metals have been identified as lead, zinc, copper, arsenic, antimony, mercury beryllium, barium, cadmium, chromium, nickel, selenium among others. Preliminary laboratory studies have been directed to the determination of traces of lead in the aquatic biota and its toxicity. There are indications that the levels reported in effluents from some of the industries may be above the tolerant limits of local fish species and organisms that make up their food. Metal pollution could become a serious problem to freshwater fisheries in the future as a result of increasing urbanization and industrialization, unless efforts are made to prevent it

Investment prospects in inland capture fisheries with special reference to small reservoirs: the exclusive fishing right licence model

The paper discusses simple methods of estimating fish yield from small reservoirs and establishes 2 indices of fish yield based on: 1) the relationship between the catch per boat in artisanal commercial fish landings and the catch per unit effort in experimental gill-net survey; and also, 2) the relationship between standing crop of fish in reservoirs and catch per unit effort in experimental gill-net survey. The paper then elaborates on the methods of utilizing these simple relationships in managing small reservoirs in Nigeria based on the principle of exclusive fishing right licence with the objective of attracting investors into this viable inland fishery investment project hitherto untapped