ResourcesIdentification of Important Habitats in Coastal New HampshireChapter 12. American LobsterThe American lobster, Homarus americanus, is a decapod crustacean
of major commercial importance in the Gulf of Maine. There is
a commercial and recreational fishery in Great Bay. The following tables
are components of a model to map lobster habitat. Most of the information
was compiled by Brown et al. (unpub.) from the sources
listed below. 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. Habitats were mapped for adult, juvenile, and reproductive stages. The
latter included the period during which females carry eggs; the short
planktonic stages were assumed not to be limiting. For each stage, habitat
suitability values were computed as the geometric mean of values for each
of four seasons. Because of the mobility of lobsters, different stages
may find required conditions at different localities. Therefore, overall
habitat was mapped as the maximum value from either juvenile, reproductive
or adult habitat maps (Figures of Adult
Habitat, Juvenile Habitat, Combined
Life Stages). SUBSTRATE PREFERENCES Sources: Able et al. 1988, Botero and Atema 1982, Brown et al., unpub., Campbell 1990, Cooper and Uzmann 1980, Wahle 1993, Phillips, Cobb and George 1980, Pottle and Elner 1982, Hudon & G. Lamarche 1989. Substrate Suitability Index: 0 to 10 scale; 0 = unsuitable, 10 = optimal condition JUVENILE
ADULT, REPRODUCTION
SALINITY PREFERENCES Sources: Brown et al., unpub., Reynolds and Casterlin 1985, Cooper and Uzmann 1980. Salinity (ppt) Suitability Index: 0 to 10 scale; 0 = unsuitable, 10 = optimal condition JUVENILE
ADULT
REPRODUCTION
TEMPERATURE PREFERENCES Sources: Brown et al., unpub., Phillips, Cobb and George 1980, Reynolds and Casterlin 1979, Reynolds and Casterlin 1985, Phillips and Sastry 1980. Temperature (C) Suitability Index: 0 to 10 scale; 0 = unsuitable, 10 = optimal condition JUVENILE
ADULT
REPRODUCTIVE
DEPTH PREFERENCES Sources: Brown et al., unpub, Campbell 1990, Ojeda and Dearborn 1989, Phillips, Cobb and George 1980. Depth (feet, mlw*) Suitability Index: 0 to 10 scale; 0 = unsuitable, 10 = optimal condition JUVENILE
ADULT, REPRODUCTIVE
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