Species Profiles: Life Histories and Environmental Requirements of Coastal Vertebrates and Invertebrates Pacific Ocean Region. Report 4. The Hawaiian Anchovy or Nehu Encrasicholina purpurea (Engraulidae)
Abstract
The nehu is a small anchovy restricted to semienclosed areas in Hawaii for most of its life cycle; some evidence indicates that nonspawning adults may move into exposed coastal habitats. Spawning occurs throughout the year but is concentrated between late summer and early winter. Incubation and development to first-feeding status require only a few days. The larvae metamorphose at a standard length of about 30 mm and an age of about 90 days. Sexual maturity occurs at 35 to 40 mm, and maximum size and age are about 65 months, respectively. Late larval, juvenile, and adult nehu typically occur in shallow areas by day and migrate into deeper water to feed at night. The diet is dominated by large zooplankton with apparent preference for crustaceans. Nehu are eaten by a variety of predators, mostly fishes. They are the major source of bait for the Hawaiian skipjack tuna fishery. Available analyses of catch and effort data give no clear evidence that the fishery has seriously impacted the population. Based on estimates of nehu consumption rates, standing crops, and fishery yields, it appears that nehu consume a large fraction of zooplankton production in semienclosed habitats in Hawaii. The physiological tolerance ranges of nehu indicate that they probably only rarely encounter deleterious conditions in nature and have, as yet, probably not been seriously impacted by human activity in coastal situations. (SDW)
Document Details
- Document Type
- Technical Report
- Publication Date
- Nov 01, 1989
- Accession Number
- ADA216653
Entities
People
- Thomas A. Clarke