Larval Atlantic Herring Clupea Harengus Research Articles

Food-limited growth of larval Atlantic herring Clupea harengus recurrently observed in a coastal nursery area

Food-limited growth of larval fish, defined as growth rates lower than observed in other habitats or from laboratory experiments at a given temperature, is rarely reported in field studies. This would imply that either larval fishes are living in an environment characterized by plenty of food, that nutritional condition selective mortality (i.e., eliminating the weak) is very strong, or this impression is caused by misinterpretation of data concerning e.g., poor taxonomical resolution of potential prey items, i.e., total potential prey abundance is high, but positively selected food is actually scarce. We analyzed RNA:DNA derived growth rates of herring larvae (Clupea harengus L.) and taxonomically differentiated prey field data of six consecutive spring seasons from the Kiel Canal, an artificial waterway in northern Germany, in order to test if food-limited growth in larval fish can occur recurrently in coastal habitats. In all years analyzed, larval growth rates decreased simultaneously with prey abundance at the end of each larval season. Furthermore, larval growth rates were observed to be lower than mean growth rates observed in another herring larvae nursery area at temperatures above 15 °C. Asymptotic relationships between prey abundance and larval growth rates were observed, further supporting the hypothesis of food-limitation. As larval growth was best explained by the abundance of the numerically dominant calanoid copepod Eurytemora affinis, the paramount importance of the dominant prey item is highlighted. We conclude that food limitation can be a severe and re-occurring issue for larval fish in coastal habitats, and that certain prey items play a crucial role in determining larval growth rates, and therefore potentially recruitment.

Relation between Winter Temperature and Survival of Larval Atlantic Herring along the Maine Coast

Abstract Larval Atlantic herring Clupea harengus, hatched mainly in late summer and autumn in Maine coastal waters, experienced relatively small temperature declines (1.8–3.1°C) during their autumn transport along the coast to two inshore overwintering locations in the early 1960s and in 1982. Larvae that reached the Sheepscot River estuary on the central Maine coast experienced rates of temperature decline from 0.04 to 0.23°C/d in the early winter of 13 years during the period 1965–1985. Winter larval survival rates were more variable at lower gradients of minimum temperature and declined to lower values at higher gradients. Age-frequency data indicated that the 1984 year-class approached metamorphosis earlier than the 1983 year-class, possibly due to accelerated growth in early spring. Minimum temperatures of 0°C or less were recorded in Boothbay Harbor during the overwintering period for nine year-classes; two of these year-classes were exposed to low temperatures (–1.1°C) that approached the lethal li...

Mortality, Growth, and Transport of Larval Atlantic Herring Clupea harengus in Maine Coastal Waters

Abstract Microstructural growth increments in otoliths of autumn-spawned, larval Atlantic herring from the Sheepscot River estuary of western Maine and Sullivan Harbor of eastern Maine provided estimates of mortality, growth, or transport times (or combinations of these) for 19 cohorts in 1980–1982. Mortality within seven cohorts averaged 2%/d (range, 0.7–3.1%/d). Growth (12 cohorts) averaged 0.199 mm/d (0.123–0.270). Transport times of larvae hatched on the spawning ground of eastern Maine and captured in the harbor and estuary (8 cohorts) averaged 16.5 d (5–35 d). Estimates of mortalities agreed (P > 0.05) with those from multicohorts obtained in the 1960s and 1970s (0.4–3.2%/d). Among the cohorts, extremes of larval growth differed significantly (P 0.05) was noted between larvae of cohorts spawned relatively early and those of a cohort spawned late. Larval mortality and growth appeared...