ResourcesIdentification of Important Habitats in Coastal New HampshireChapter 11. PollockThe pollock, Pollachius virens, is a gadid (cod-like) fish,
typically found in deep waters of the Gulf of Maine south to the Carolinas.
Pollock are harvested commercially, with a limited recreational fishery.
The following tables are components of a pollock habitat model, based
on information compiled from the literature and by examination
of conditions associated with fish collection sites in Great Bay (Nelson
et al. 1981). The model operates on four parameters: substrate, salinity, temperature,
and depth. The model indexes the relative suitability of each environmental
parameter on a 0 to 10 basis, with 10 being optimal and 0 being unsuitable.
These suitability index values are combined by computing their geometric
mean for each grid-cell in the study area. Thus, optimal habitat for any
life stagewould occur where the index values were the maximum for each
of the four inputs; no value is attributed to areas where any condition
is completely unsuitable. Suitability is calculated for each season, to
accommodate annual changes in salinity and temperature. Only juvenile pollock ("harbor pollock") are found in relatively shallow
inshore waters, such as Great Bay and the Seabrook/Hampton estuary. Habitats
were mapped for conditions needed by juveniles during the spring, summer
and fall of the year. Since this fish is highly mobile and able to avoid
seasonally unsuitable conditions, habitat values were based on the maximum
or most favorable score of these seasons (Figure
of Juvenile Habitat). SUBSTRATE PREFERENCES Sources: MacDonald et al. 1984, Ojeda and Dearborn 1990, Rangeley and Kramer 1995a. Substrate Suitability Index: 0 to 10 scale; 0 = unsuitable, 10 = optimal condition
SALINITY PREFERENCES Sources: MacDonald et al. 1984, Rangeley and Kramer 1995b. Salinity (ppt) Suitability Index: 0 to 10 scale; 0
= unsuitable, 10 = optimal condition
TEMPERATURE PREFERENCES Sources: Bigelow and Schroeder 1953, MacDonald et al. 1984, Ojeda and Dearborn 1990, Rangeley and Kramer 1995b, Scott and Scott 1988. Temperature (C) Suitability Index: 0 to 10 scale; 0 = unsuitable, 10 = optimal condition
DEPTH PREFERENCES Sources: Bigelow and Schroeder 1953, MacDonald et al. 1984, Rangeley and Kramer 1995a. Depth (feet, mlw*) Suitability Index: 0 to 10 scale; 0 = unsuitable, 10 = optimal condition
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