Distribution of Atlantic menhaden, Brevoortia tyrannus, purse-seine sets and catches from southern New England to North Carolina, 1985-96

Sets and catches of Atlantic menhaden, Brevoortia tyrannus, made in 1985-96 by purse-seine vessels from Virginia and North Carolina were studied by digitizing and analyzing Captain's Daily Fishing Reports (CDFR's), daily logs of fishing activities completed by captains of menhaden vessels. 33,674 CDFR's were processed, representing 125,858 purse-seine sets. On average, the fleet made 10,488 sets annually. Virginia vessels made at least one purse-seine set on 67%-83% of available fishing days between May and December. In most years, five was the median number of sets attempted each fishing day. Mean set duration ranged from 34 to 43 minutes, and median catch per set ranged from 15 to 30 metric tons (t). Spotter aircraft assisted in over 83% of sets overall. Average annual catch in Chesapeake Bay (149,500 t) surpassed all other fishing areas, and accounted for 52% of the fleet's catch. Annual catch from North Carolina waters (49,100 t) ranked a distant second. Fishing activity in ocean waters clustered off the Mid-Atlantic states in June-September, and off North Carolina in November-January. Delaware Bay and the New Jersey coast were important alternate fishing grounds during summer. Across all ocean fishing areas, most sets and catch occurred within 3 mi. of shore, but in Chesapeake Bay about half of all fishing activity occurred farther offshore. In Virginia, areas adjacent to fish factories tended to be heavily fished. Recent regulatory initiatives in various coastal states threaten the Atlantic menhaden fleet's access to traditional nearshore fishing grounds. (PDF file contains 26 pages.)

The results of an exploratory fishery cruise for Loligo Opalescens in southern and central California, June 5-25, 1974

During June 1974 the California Department of Fish and Game, in cooperation with the Sea Grant program at Moss Landing Marine Laboratories, conducted an exploratory fishing cruise that extended from La Jolla to Santa Cruz and included the Channel Islands, concentrating on inshore waters. The cruise was preliminary to the initiation of a major program of squid research and had six objectives: 1) To gather samples of market squid (Lo1igo opa1escens) for population, growth, aging and food chain studies. 2) To locate potential new fishing grounds. 3) To investigate methods for determining spawning intensity. 4) To gather data on oceanographic parameters of the spawning grounds. 5) To make incidental collections as requested by other investigators. 6) To familiarize Sea Grant personnel with the capabilities of the Department's largest research vessel, ALASKA, with respect to squid. Especially good weather and oceanographic conditions persisting throughout the cruise enabled us to make 66 night1ight stations, 17 midwater trawls and eight bottom trawls. Fishable concentrations of squid were discovered in the areas between Cape San Martin and Partington Point, between Pfeiffer Point and Point Sur, and in Carmel Bay, heretofore unfished. Squid spawning off Santa Cruz Island was observed utilizing an underwater observation chamber aboard the vessel. Mating and feeding behavior were observed in shipboard aquaria. PDF contains 28 pages)

Aktuelle Planungen zur Regelung der Beifangproblematik in der Krabbenfischerei

At present the fishery for the brown shrimp (Crangon crangon L.) is one of the most economically rewarding fisheries in Europe. Due to the small size of the target objects this fishery has to be carried out with rather small meshes. As it is, however, performed on the nursing grounds of important fish species it encounters a severe bycatch problem. On this basis, EU Council regulation 850/98 demands the use of either sieve nets or sorting grids from 1 July, and to pass pertaining national bye-laws. Germany discusses to use either sieve nets of 70 mm mesh opening or sorting grids of 20 mm bar distance, and tries to achieve a harmonization of the byelaw with neighbouring countries of The Netherlands and Denmark to ensure equal conditions on the same fishing grounds.

Spawning of yellowfin tuna and the discrimination of subpopulations

ENGLISH: The spawning of yellowfin tuna (Thunnus albacares) in the eastern Pacific Ocean was examined to ascertain the existence of separate subpopulations within this area. Investigations of biochemical genetics of yellowfin indicate that there are a number of genetically distinct groups in the eastern Pacific. In addition, yellowfin belong to two recruitment cohorts, X and Y, which are composed of a mixture of these genetically different groups. Spawning data were collected from 1956 through 1961 from the coastal fishing grounds, and from 1970 through 1973 from the offshore fishing areas. Temporal and spatial aspects of spawning of the fish of the two cohorts were analyzed to determine if yellowfin spawning behavior supports the existence of genetically separate subpopulations. Spawning condition was inferred from the maturity of the ovaries. It was found that the coastal fish of each cohort exhibit at least two spawning periods per year which vary in length and time of occurrence from year to year. Fish taken from the offshore fishing grounds did not exhibit this variable spawning pattern. Although samples were not available for all months, the data showed that each cohort has a spawning period of at least 7 months and may spawn year around. Samples from offshore areas also had much higher percentages of spawners than those from the coastal areas. Temporal differences in spawning are not maintaining the genetically separate groups found in the fishery, since fish of both recruitment cohorts spawn at the same time. Also, fish of both the X and Y cohorts spawned in all areas examined; however, these data are insufficient to determine whether spatial isolation of spawning groups is occurring within the areas. SPANISH: Se examinó el desove del atún aleta amarilla (Thunnus albacares) en el Océano Pacífico oriental para averiguar la existencia de subpoblaciones separadas en esta zona. La investigación genética bioquímica del aleta amarilla indica que existen varios grupos genéticamente distintos en el Pacífico oriental. Además, el aleta amarilla pertenece a dos cohortes de reclutamiento X e Y, formadas por una mezcla de estos grupos genéticamente diferentes. Los datos del desove fueron obtenidos de 1956 a 1961, en las regiones neríticas de pesca y desde 1970 a 1973, en las áreas oceánicas de pesca. Se analizaron los aspectos temporales y espaciales del desove de los peces de las dos cohortes, para determinar si el comportamiento reproductor del aleta amarilla, apoya la existencia de subpoblaciones genéticamente diferentes. Se derivó la condición del desove según la madurez de los ovarios. Se encontró que los peces costeros de cada cohorte exhibían por lo menos dos períodos anuales de desove que varían en duración y fecha de ocurrencia de un año a otro. Los peces capturados en las regiones oceánicas de pesca no exhibieron este patrón variable de desove. Aunque o se consiguieron muestras en todos los meses, los datos indican que cada cohorte tiene un período de desove por lo menos de 7 meses y puede que desoven durante todo el año. Las muestras de las regiones oceánicas tuvieron porcentajes mucho mayores de reproductores que los de las zonas neríticas. Las diferencias temporales en el desove no sirven para explicar la presencia de grupos genéticamente separados que se encuentran en la pesca, ya que los peces de ambas cohortes de reclutamiento desovan al mismo tiempo. Además, los peces de ambas cohortes (X e Y) desovan en todas las zonas examinadas; sin embargo, estos datos no son suficientes para determinar si el aislamiento de los grupos de desove ocurre en las zonas. (PDF contains 53 pages.)

Analyse der Beifangreduktion durch Gitternetze in der kommerziellen Garnelenfischerei

Trials for the determination of the magnitude of bycatch reduction by sorting grids used in the commercial brown shrimp fishery were carried out from September to December 1997. Trawls with 9 m beam length were used on different fishing grounds in the estuary of the Elbe River near Cuxhaven. The sorting grids tested were made of stainless steel bars spaced at 18, 20, 22, 26 and 30 mm, built into a cylindrical stainless steel frame with a diameter of 65 cm at an angle of attack of 45 degrees. This frame was positioned between the forenet and codend. Simultaneous hauls were made with a trawl of equal construction but without a sorting grid, and the weighed catch components (fish, discard shrimps and commercial size shrimps) separated by means of a riddle were compared. The composition of the sorted out part of the catch of the sorting grid net could be calculated by comparise the corresponding catch components in both the standard trawl and the sorting grid trawl. According to this the total catch of the beam trawl with the sorting grid is reduced by 18 to 38 % depending on the space between the bars. 7 to 31 % of the sorted out part of the catch consists of fish. The use of the sorting grid, however, also leads to losses of 4 to 12 % in Oktober. Per hour of towing this means a loss of 10,3 % commerical size shrimps with a sorting grid of 18 mm space between the bars and of 12,4 % for a 26 mm grid.

Entwicklungstendenzen der Steinbuttfischerei in der Ostsee

The economical value of turbot (Psetta maxima) from the Baltic Sea has distinctly increased in the past decade. Compared to the eighties the catches of this species on the main fishing grounds increased threefold. Besides a more directed fishery on this species and an improved catch statistic the main reason for this fact is probably an increased stock size. Improved protection measures caused three consecutive strong year-classes. The main parameters of the turbot stock are presented.

Deutsche und internationale Dorschfischerei in der Ostsee im Jahr 1998

In 1998 the longtime series of the standardized bottom trawl surveys conducted in the western Baltic (ICES Sub-division (SD) 22 and 24 since 1978) during spring and autumn and also in the eastern Baltic (ICES Sub-division since 1993) during spring were continued. The results of the surveys as well as those of a sampling programme carried out on board of commercial cutters (mainly financed by an EU study project) and on the market, the investigation of the survival rate of the discards, and the landing statistics are the basis of the analysis of the German and international cod fishery in 1998. The German cod fishery was concentrated on the ICES SD 22 and 24 (total landings 9722 t). The total landings from the fishing grounds east off Bornholm, the traditional German fishing ground, amounted only to about 1270 t. The German cod quota was utilized at 64 %. The fishery in the ICES SD 22 and 24 was characterized by a discard rate of undersized cod of 13 %. That corresponds to about 7.3 million specimens of 0-group, one- and two-years-old youngfish, respectively. The total international cod landings of the Baltic amounted to 101 500 t. In comparison with 1997 (total landings 129 600 t) the landing decreased by 23 %. The percentage utilization of the cod TAC (1998: 140 000 t) amounted to 74 % in 1998.

Fangtechnische Möglichkeiten zur Reduzierung des Beifangs von Meeresenten in der Dorschfischerei mit stationären Fanggeräten

The present contribution summarizes results of fishery investigations with gillnets and longlines in the winter cod fishery which had been carried out in the western Baltic region from 1996 to 1999 by the Bundesforschungsanstalt für Fischerei with financial aid of the country Schleswig-Holstein. The main goal of these investigations was to point out technological possibilities for a reduction of unwanted bycatches of sea ducks in gillnetting. As it is obviously impossible to reduce the local and temporal bycatch problem by means of different gillnet constructions or tactical measurements, only the temporary avoidance of fishing grounds with high abundance of ducks or the change to longlining as catch method with reduced duck bycatches may be an effective solution.

Analyse der Beifangreduktion durch Trichternetze in der kommerziellen Garnelenfischerei

Trials for the determination of the magnitude of bycatch reduction by the sievenets used in the commercial brown shrimp fishery were carried out from September to December 1997. Trawls with 9 m beam length were the subjected to the investigation. They were used on different fishing grounds in the estuary of the Elbe near Cuxhaven. Sievenets with 50, 60 and 80 mm mesh opening were tested in 29 hauls and 31.6 h total duration. A trawl of equal construction without sievenets fished synchronously was used for comparison. The proportional catch composition in the codend was determined by weighing the catch components (fish, discard shrimps and commercial size shrimps) as separated by means of a riddle. The composition of the sorted out part of the catch could be calculated by comparison of the corresponding catch components both in standard trawl and sievenettrawl. According to this the total catch of a beam trawl with sievenet is diminished by 9 to 34 % depending on the mesh opening of the sievenet. 32 to 58 % of the sorted out part of the catch consists of fish. Use of a sievenet, however, also leads to a loss of 6 to 15 % of commercial size shrimps. Per hour of towing this means a loss of 8.7 kg commercial size shrimps with a sievenet of 60 mm mesh opening and of 1.8 kg for a mesh size of 80 mm.

Analysis of variance and standardization of longline hook rates of bigeye (Thunnus obesus) and yellowfin (Thunnus albacares) tunas in the Eastern Pacific Ocean during 1975-1987

ENGLISH: Longline hook rates of bigeye and yellowfin tunas in the eastern Pacific Ocean were standardized by maximum depth of fishing, area, and season, using generalized linear models (GLM's). The annual trends of the standardized hook rates differ from the unstandardized, and are more likely to represent the changes in abundance of tunas in the age groups most vulnerable to longliners in the fishing grounds. For both species all of the interactions in the GLM's involving years, depths of fishing, areas, and seasons were significant. This means that the annual trends in hook rates depend on which depths, areas, and seasons are being considered. The overall average hook rates for each were estimated by weighting each 5-degree quadrangle equally and each season by the number of months in it. Since the annual trends in hook rates for each fishing depth category are roughly the same for bigeye, total average annual hook rate estimates are possible with the GLM. For yellowfin, the situation is less clear because of a preponderance of empty cells in the model. The full models explained 55% of the variation in bigeye hook rate and 33% of that of yellowfin. SPANISH: Se estandardizaron las tasas de captura con palangre de atunes patudo y aleta amarilla en el Océano Pacífico oriental por la profunidad máxima de pesca, área, y temporada, usando modelos lineales generalizados (MLG). Las tendencias anuales de las tasas de captura estandardizadas son diferentes a las de las tasas no estandardizadas, y es más que representen los cambios en la abundancia de los atunes en los grupos de edad más vulnerables a los palangreros en las áreas de pesca. Para ambas especies fueron significativas todas las interacciones en los MLG con año, profundidad de pesca, área, y temporada. Esto significa que las tendencias anuales de las tasas de captura dependen de cuál profundidad, área, y temporado se está considerando. Para la estimación de la tasa de captura general media para cada especie se ponderó cada cuadrángulo de 5 grados igualmente y cada temporada por el número de meses que contiene. Ya que las tendencias anuales en las tasas de captura para cada categoría de profundidad de pesca son aproximadamente iguales para el patudo, son posibles estimaciones de la tasa de captura anual media total con el MLG. En el caso del aleta amarilla, la situación es más confusa, debido a una preponderancia de celdas vacías en el modelo. Los modelos completos explican el 55% de la variación de la tasa de captura de patudo y 33% de la del aleta amarilla. (PDF contains 19 pages.)

Catches per unit of effort of bigeye tuna: a new analysis with regression trees and simulated annealing

ENGLISH: We analyzed catches per unit of effort (CPUE) from the Japanese longline fishery for bigeye tuna (Thunnus obesus) in the central and eastern Pacific Ocean (EPO) with regression tree methods. Regression trees have not previously been used to estimate time series of abundance indices fronl CPUE data. The "optimally sized" tree had 139 parameters; year, month, latitude, and longitude interacted to affect bigeye CPUE. The trend in tree-based abundance indices for the EPO was similar to trends estimated from a generalized linear model and fronl an empirical model that combines oceanographic data with information on the distribution of fish relative to environmental conditions. The regression tree was more parsimonious and would be easier to implement than the other two nl0dels, but the tree provided no information about the nlechanisms that caused bigeye CPUEs to vary in time and space. Bigeye CPUEs increased sharply during the mid-1980's and were more variable at the northern and southern edges of the fishing grounds. Both of these results can be explained by changes in actual abundance and changes in catchability. Results from a regression tree that was fitted to a subset of the data indicated that, in the EPO, bigeye are about equally catchable with regular and deep longlines. This is not consistent with observations that bigeye are more abundant at depth and indicates that classification by gear type (regular or deep longline) may not provide a good measure of capture depth. Asimulated annealing algorithm was used to summarize the tree-based results by partitioning the fishing grounds into regions where trends in bigeye CPUE were similar. Simulated annealing can be useful for designing spatial strata in future sampling programs. SPANISH: Analizamos la captura por unidad de esfuerzo (CPUE) de la pesquería palangrera japonesa de atún patudo (Thunnus obesus) en el Océano Pacifico oriental (OPO) y central con métodos de árbol de regresión. Hasta ahora no se han usado árboles de regresión para estimar series de tiempo de índices de abundancia a partir de datos de CPUE. EI árbol de "tamaño optimo" tuvo 139 parámetros; ano, mes, latitud, y longitud interactuaron para afectar la CPUE de patudo. La tendencia en los índices de abundancia basados en árboles para el OPO fue similar a las tendencias estimadas con un modelo lineal generalizado y con un modelo empírico que combina datos oceanográficos con información sobre la distribución de los peces en relación con las condiciones ambientales. EI árbol de regresión fue mas parsimonioso y seria mas fácil de utilizar que los dos otros modelos, pero no proporciono información sobre los mecanismos que causaron que las CPUE de patudo valiaran en el tiempo y en el espacio. Las CPUE de patudo aumentaron notablemente a mediados de los anos 80 y fueron mas variables en los extremos norte y sur de la zona de pesca. Estos dos resultados pueden ser explicados por cambios en la abundancia real y cambios en la capturabilidad. Los resultados de un arbal de regresión ajustado a un subconjunto de los datos indican que, en el OPO, el patudo es igualmente capturable con palangres regulares y profundos. Esto no es consistente con observaciones de que el patudo abunda mas a profundidad e indica que clasificación por tipo de arte (palangre regular 0 profundo) podría no ser una buena medida de la profundidad de captura. Se uso un algoritmo de templado simulado para resumir los resultados basados en el árbol clasificando las zonas de pesca en zonas con tendencias similares en la CPUE de patudo. El templado simulado podría ser útil para diseñar estratos espaciales en programas futuros de muestreo. (PDF contains 45 pages.)

Pressures on the biota in the aquatic ecosystem of (Chi) Cross River National Park, Okwango Division

A preliminary survey of Cross River National Park (Nigeria), Okwangwo Division was carried out. The combined natural and human pressures being exerted on the aquatic resources were also investigated. Information on the existing fishing communities in and around the park area are given. The fishermen, their fishing methods and fishing grounds were identified. Limiting factors (natural and human) to the fisheries production, are analysed. Positive measures for conservation, protection and management of healthy and natural aquatic environment are suggested

An assessment of co-management potentials in the Lake Victoria fisheries of Kenya

Co-management is a system or a process in which responsibility and authority for the management of common resources is shared between the state, local users of the resources as well as other stakeholders, and where they have the legal authority to administer the resource jointly. Co-management has received increasing attention in recent years as a potential strategy for managing fisheries. This paper presents and discusses results of a survey undertaken in the Kenyan part of Lake Victoria to assess the conditions - behaviour, attitude and characteristics of resource users, as well as community institutions - that can support co-management. It analyses the results of this survey with respect to a series of parameters, identified by Pinkerton (1989), as necessary preconditions for the successful inclusion of communities involvement in resource management. The survey was implemented through a two-stage stratified random sampling technique based on district and beach size strata. A total of 405 fishers, drawn from 25 fish landing beaches, were interviewed using a structured questionnaire. The paper concludes that while Kenya's lake Victoria fishery would appear to qualify for a number of these preconditions, it would appear that it fails to qualify in others. Preconditions in this latter category include the definition of boundaries in fishing grounds, community members' rights to the resource, delegation and legislation of local responsibility and authority. Additional work is required to further elaborate and understand these shortcomings

Survey of the shrimp stocks of the Sierra Leone inshore shelf : a summary report outlining objectives, observations and recommendations on the status of the Sierra Leone shrimp fishery

This report gives the species and catch-rates per hour of some commercial shrimp species caught in the course of a short survey of inshore shelf fishing grounds. Species seen in significant quantities were: Parapenneopsis atlantica, Parapenaeus longirostris, Penaeus kerathurus and Penaeus duorarum notialis

Fettgehalte von Makrelen in Abhängigkeit von der Größe, dem Fanggebiet und der Jahreszeit

Data on the fat content in the edible part of mackerel in correlation to the length are given for nine different fishing grounds. The samples were taken in spring and summer in the North Sea, west and south of the British Isles and in the bay of Biscay.