GRANT
NUMBER: NA16FL0068
NMFS NUMBER:
90-NER-010
REPORT
TITLE:
Assessment
of Juvenile Bycatch Survivability in the Northeast Fishing
Industry
AUTHOR:
Robinson,
William E. and Carr, H. Arnold
PUBLISH
DATE:
May
11, 1993
AVAILABLE
FROM:
National Marine Fisheries Service, Northeast Region, One
Blackburn Drive, Gloucester, MA 01930-2298. PHONE:
(508) 281-9256
ABSTRACT

The objective
of this project was to assess the juvenile bycatch survivability
of cod and other important groundfish species. Survival
data was collected on three bottom-dwelling species, one
gadoid (Atlantic cod) and two flatfish (American plaice
and yellowtail flounder). Yellowtail flounder exhibited
the greatest resistance to fishing induced stress. Plaice
were intermediate in survivability, with Atlantic cod
being the most susceptible to fishing-induced mortality.
Cod and plaice experienced lower mortality during the
April survey than during the June survey, indicating that
the higher surface water and air temperatures, and/or
differences in other environmental parameters during the
warmer summer months may have a profound effect on survival.
The nonparametric statistics used in this study to determine
the degree to which the various environmental factors
affect survivability indicated that cod survival was influenced
by air temperature, deck time, fish length, tow duration
and tow weight, whereas plaice survival was impacted by
air temperature and deck time. The ability of these nonparametric
statistics to detect relationships depended heavily on
adequate sample size, which was not always present. The
information gathered during this investigation provides
a strong basis to determine actual survival of cod, plaice
and yellowtail during different seasons. Indications
are that the cod-end escapees of the three species had
high survival rates (>91 percent). This high survival
rate supports the concept of conservation by using selective
trawl gear that will release juvenile groundfish.