The movements of salmon in relation to variations in air and water temperatures

The temperature of water in a river system affects fish in various ways; it has an influence on feeding habits, movement and metabolism. All fish vary in their ability to tolerate fluctuations in temperature, but those that live in a reasonably stable environment are more sensitive to major changes (tropical fish) than are salmon which can tolerate abrupt changes. The body temperature of the majority of fish differs from that of the surrounding water by only 0.5 to 1.0 degrees, and changes in temperature can, in many cases, be a signalling factor for some process, for example spawning, migration or feeding. It has been found, after monitoring the activity in 2,623 salmon in the River Lune, that they live in a water temperature of 0-17 degrees. Whilst salmon ova can develop in a temperature range of 0-12 degrees, spawning takes place within a much closer range, and these tolerances will be found in the Report. This report offers data and analysis of fish movement correlated to water temperature for the years 1964/65.

The movements of salmon in relation to daylight

This report covers the upstream movement of 1,719 salmon in the River Leven during the year 1965. An analysis of river levels taken at hourly intervals from April to November 1965 correlated to fish movement at the exact river level when fish moved is provided. The report concludes that major quantities of water from the Rivers Lune and Leven can be made available for domestic and industrial supply without harming the fisheries.

Distribution, movements, and habitat use of small striped bass (Morone saxatilis) across multiple spatial scales

Distribution, movements, and habitat use of small (<46 cm, juveniles and individuals of unknown maturity) striped bass (Morone saxatilis) were investigated with multiple techniques and at multiple spatial scales (surveys and tag-recapture in the estuary and ocean, and telemetry in the estuary) over multiple years to determine the frequency and duration of use of non-natal estuaries. These unique comparisons suggest, at least in New Jersey, that smaller individuals (<20 cm) may disperse from natal estuaries and arrive in non-natal estuaries early in life and take up residence for several years. During this period of estuarine residence, individuals spend all seasons primarily in the low salinity portions of the estuary. At larger sizes, they then leave these non-natal estuaries to begin coastal migrations with those individuals from nurseries in natal estuaries. These composite observations of frequency and duration of habitat use indicate that non-natal estuaries may provide important habitat for a portion of the striped bass population.

Postrelease survival, vertical and horizontal movements, and thermal habitats of five species of pelagic sharks in the central Pacific Ocean

From 2001 to 2006, 71 pop-up satellite archival tags (PSATs) were deployed on five species of pelagic shark (blue shark [Prionace glauca]; shortfin mako [Isurus oxyrinchus]; silky shark [Carcharhinus falciformis]; oceanic whitetip shark [C. longimanus]; and bigeye thresher [Alopias superciliosus]) in the central Pacific Ocean to determine species-specific movement patterns and survival rates after release from longline fishing gear. Only a single postrelease mortality could be unequivocally documented: a male blue shark which succumbed seven days after release. Meta-analysis of published reports and the current study (n=78 reporting PSATs) indicated that the summary effect of postrelease mortality for blue sharks was 15% (95% CI, 8.5–25.1%) and suggested that catch-and-release in longline fisheries can be a viable management tool to protect parental biomass in shark populations. Pelagic sharks displayed species-specific depth and temperature ranges, although with significant individual temporal and spatial variability in vertical movement patterns, which were also punctuated by stochastic events (e.g., El Niño-Southern Oscillation). Pelagic species can be separated into three broad groups based on daytime temperature preferences by using the unweighted pair-group method with arithmetic averaging clustering on a Kolmogorov-Smirnov Dmax distance matrix: 1) epipelagic species (silky and oceanic whitetip sharks), which spent >95% of their time at temperatures within 2°C of sea surface temperature; 2) mesopelagic-I species (blue sharks and shortfin makos, which spent 95% of their time at temperatures from 9.7° to 26.9°C and from 9.4° to 25.0°C, respectively; and 3) mesopelagic-II species (bigeye threshers), which spent 95% of their time at temperatures from 6.7° to 21.2°C. Distinct thermal niche partitioning based on body size and latitude was also evident within epipelagic species.

Diversity of estuarine movements of striped bass (Morone saxatilis): a synoptic examination of an estuarine system in southern New Jersey

We determined the dis-tribution of multiple (n=68; 508−978 mm total length [TL]) striped bass (Morone saxatilis) along the estua-rine salinity gradient in the Mullica River−Great Bay in southern New Jersey over two years to determine the diversity of habitat use and the movements of striped bass. Ultrasoni-cally tagged fish were detected in this estuarine area by means of wireless hydrophones deployed at four gates inside the entrance of the study area and farther up to tidal freshwater (38 km). Numerous individuals frequently departed and returned to the estuary, primarily in the spring and late fall over periods of 15−731 days at liberty. The period of residency and degree of movement of individuals to and from the estuary varied extensively among seasons and years. The diversity of movements in and out of, as well as within, the estuary differed from the less-complex patterns reported in earlier studies, perhaps because of the comprehensive and synoptic nature of this study.

Movements and spawning of white marlin (Tetrapturus albidus) and blue marlin (Makaira nigricans) off Punta Cana, Dominican Republic

With a focus on white marlin (Tetrapturus albidus), a concurrent electronic tagging and larval sampling effort was conducted in the vicinity of Mona Passage (off southeast Hispaniola), Dominican Republic, during April and May 2003. Objectives were 1) to characterize the horizontal and vertical movement of adults captured from the area by using pop-up satellite archival tags (PSATs); and 2) by means of larval sampling, to investigate whether fish were reproducing. Trolling from a sportfishing vessel yielded eight adult white marlin and one blue marlin (Makaira nigricans); PSAT tags were deployed on all but one of these individuals. The exception was a female white marlin that was unsuitable for tagging because of injury; the reproductive state of its ovaries was examined histologically. Seven of the PSATs reported data summaries for water depth, temperature, and light levels measured every minute for periods ranging from 28 to 40 days. Displacement of marlin from the location of release to the point of tag pop-up ranged from 3l.6 to 267.7 nautical miles (nmi) and a mean displacement was 3.4 nmi per day for white marlin. White and blue marlin mean daily displacements appeared constrained compared to the results of other marlin PSAT tagging studies. White marlin ovarian sections contained postovulatory follicles and final maturation-stage oocytes, which indicated recent and imminent spawning. Neuston tows (n=23) yielded 18 istiophorid larvae: eight were white marlin, four were blue marlin, and six could not be identified to species. We speculate that the constrained movement patterns of adults may be linked to reproductive activity for both marlin species, and, if true, these movement patterns may have several implications for management. Protection of the potentially important white marlin spawning ground near Mona Passage seems warranted, at least until further studies can be conducted on the temporal and spatial extent of reproduction and associated adult movement.

A Brief Interpretation of Summer Flounder, Paralichthys dentatus, Movements and Stock Structure with New Tagging Data on Juveniles

Summer flounder, Paralichthys dentatus, are managed as a single stock along the Atlantic coast from the U.S.– Canada border to the southern border of North Carolina. Justification of the single-stock approach is based on lack of genetic evidence for multiple stocks and the difficulty presented by managing the species from Cape Hatteras to the U.S.–Canada border. In this review, we present an interpretation of various morphometric, meristic, biochemical, and tagging studies, published and unpublished, that indicate the presence of two, or possibly three, distinct stocks in the management area. In addition, we have included new data from a tagging study that was conducted on juveniles from Virginia that aids in defining the stock(s) north of Cape Hatteras. Summer flounder, overfished for the past two decades, is recovering, and reconsideration of proposed stock structure could have direct implications for management policy decisions.

Blue Marlin, Makaira nigricans, Movements in the Western North Atlantic Ocean: Results of a Cooperative Game Fish Tagging Program, 1954-88

Blue marlin, Makaira nigricans, tag and recapture data are summarized for 1954-1988. During this period, 8,447 fish have been tagged and only 30 (0.35 percent) have been returned. Results of the tagging program indicate that blue marlin not only travel considerable distances (7,OOO km from the U. S. Virgin Islands to the Ivory Coast of West Africa), but have remained at large for up to 8 years. Seasonal movements, however, are difficult to determine accurately.