Stations cotières et station Vridi: exploitation des données des années 1984 et 1985

Along the Ivorian seaboard we have seven (7) stations where sea water temperature is measured every morning between 7:30 and 8:00. The hydrologic station of Vridi located at point A (5°05N, 4°05W) is generally exploited twice a week. In this report we are going to deal with data collected in 1984 and 1985. The irregularity of the dynamic height at point A enables us to identify water masses that go over the continental plateau.

Summary of fishery statistics, 1984

This fisheries report summarises developments of the year 1984 in the region of the North West Water Authority. It provides catch statistics, rod and line and commercial catches for salmon and sea trout, fish culture and hatchery operations, restocking with trout and freshwater fish, upstream fish movement recorded at Authority fish counters, counts of salmon and sea trout spawning redds, fish mortalities, licences issued, and prosecutions.

The Gache Gache Fishing Co-operative, July 1984-June 1985

Details are given of development of the Gache Gache Fishing Cooperative and fishing activities in Lake Kariba undertaken during the year June 1984-June 1985. The viability of fishing cooperatives in Lake Kariba is also examined.

1984 fisheries statistics, Lake Kariba - Zimbabwe side

Statistics are presented for the Zimbabwe fisheries of Lake Kariba for 1984, being divided into pelagic and inshore fishery activities.

Contents of No. 39, 1984

Table of Contents.

Regional Fisheries Advisory Committee Meeting 30th January, 1984

This is the report from the Regional Fisheries Advisory Committee meeting, which was held on the 30th January, 1984. The report contains information on the use of fyke nets and an application to use Rotenone fish Toxicant. Also included is information on Dunsop Trout Farm and the establishment of migratory fish rearing facilities, the decline of salmon and sea trout catches in South Cumbria, and the decline of salmon stocks in the River Eden. The Fisheries Advisory Committee was part of the Regional Water Authorities, in this case the North West Water Authority. This preceded the Environment Agency which came into existence in 1996.

Regional Fisheries Advisory Committee Meeting 18th June, 1984

This is the report from the Regional Fisheries Advisory Committee meeting, which was held on the 18th June, 1984. The report contains information on fishing licence duties, the Flimby Arrangement and the Disease of Fish Acts 1937 and 1983. Also covered is the use of Rotenone in the Lancaster Canal at Stainton, and the Salmon and Freshwater Fisheries Act, 1975. The Fisheries Advisory Committee was part of the Regional Water Authorities, in this case the North West Water Authority. This preceded the Environment Agency which came into existence in 1996.

Regional Fisheries Advisory Committee Meeting 15th October, 1984

This is the report from the Regional Fisheries Advisory Committee meeting, which was held on the 15th October, 1984. The report contains sections on Grass Carp Field Trials in the Lancaster Canal, liaisons with Sea Fisheries Committees, Rivers Leven and Crake migratory fish stocking, and migratory fish stocking policy. The Fisheries Advisory Committee was part of the Regional Water Authorities, in this case the North West Water Authority. This preceded the Environment Agency which came into existence in 1996.

Topic 1. Some steric-height features of the water off the Pacific coast of Canada; Topic 2. Possible warming of the water at station P in the northeast Pacific during 1956-1984 [abstract]

TOPIC 1: In terms of seasonal scale, temperature effect dominates the annual change of steric height in the open ocean whereas salinity effect controls it along the continental shelf. Large portion of the annual change of height relative to the 1000-db surface is contained in the upper 100m layer. However, in interannual scale large anomalies of steric height in the open ocean, are more often than not, caused by halosteric rather than thermosteric effect. At least in the open ocean the heights are almost totally determined by the behavior of deep water. Their interannual variability appears to be related to the cumulative effect of Eckman pumping. TOPIC 2: There is a "trend" that over the past 28 years the water at Station P has warmed. Least-square analysis indicates that this warming may be significant but shortening of the time-series data by approximately 10 years fails to show that this is the case. These "trends" have to be interpreted with care. The warming may be "apparent" in that it is not indicated clearly in the deep isopynal surfaces which, during the above period, have deepened. Thus warming at the isobaric surfaces may be the effect of the downward migration of the isopynal surfaces.

Changes over time in the spatial distribution of walleye pollock (Theragra chalcogramma) in the Gulf of Alaska, 1984-1996

Triennial bottom trawl survey data from 1984 to 1996 were used to evaluate changes in the summer distribution of walleye pollock in the western and central Gulf of Alaska. Differences between several age groups of pollock were evaluated. Distribution was examined in relation to several physical characteristics, including bottom depth and distance from land. Interspecies associations were also analyzed with the Bray-Curtis clustering technique to better understand community structure. Our results indicated that although the population numbers decreased, high concentrations of pollock remained in the same areas during 1984–96. However, there was an increase in the number of stations where low-density pollock concentrations of all ages were observed, which resulted in a decrease in mean population density of pollock within the GOA region. Patterns emerging from our data suggested an alternative to Mac-Call’s “basin hypothesis” which states that as population numbers decrease, there should be a contraction of the population range to optimal habitats. During 1984–96 there was a concurrent precipitous decline in Steller sea lions in the Gulf of Alaska. The results of our study suggest that decreases in the mean density of adult pollock, the main food in the Steller sea lion diet, combined with slight changes in the distribution of pollock (age-1 pollock in particular) in the mid-1980s, may have contributed to decreased foraging efficiency in Steller sea lions. Our results support the prevailing conceptual model for pollock ontogeny, although there is evidence that substantial spawning may also occur outside of Shelikof Strait.