64
Paul T. Jacobson
tions have since deteriorated. Attempts to reintroduce Atlantic Salmon earlier in
this century failed; however, Pacific Salmon were considered a feasible option
because they are more tolerant of water quality conditions to which they would be
exposed in the lower Delaware River.
The proposed program included monitoring of returning adults. Monitoring
was to begin 3 years after the first Chinook were stocked and to continue for 6
years after the last year of stocking. Elements of the monitoring/managerial program included marking or tagging of stocked fish, monitoring of movements of
returning adults, creation of a public awareness program, seasonal closure of the
lower Muscenetcong River, continuation of the statewide ban on snagging, and
collection of resource use and socioeconomic data. Because monitoring would
occur for at least 6 years beyond the last year of stocking, no action on a permanent program would occur for at least 11 years (Versar 1992a).
The experimental stocking and monitoring program was intended to provide
the information needed to assess the feasibility and advisability of a large-scale,
long-term program. If NJDFGW decided on the basis of the experimental program to proceed with a large-scale program, the data acquired from the monitoring program would be used to support a supplemental EIS.
Many of the potential environmental impacts identified by concerned citizens
during the NEPA issue scoping process derive from straying by returning salmon.
Examples of these impacts are colonization of streams, competition with native
and previously introduced salmonids in the upper Delaware River watershed, and
genetic depletion in a naturalized stock of Rainbow Trout in the upper Delaware
River basin. The level of risk associated with these concerns is related to the
probability and magnitude of straying. Thus, the risk assessment focused on
straying. The preferred species, Chinook Salmon, and two alternative species,
Coho Salmon and Steelhead Trout, were examined in the risk assessment.
Straying Model
Methods
Given the high degree of uncertainty and variability in factors that contribute to
straying, a probabilistic approach is a useful means of evaluating potential levels
of straying associated with stocking of anadromous salmonids. A Monte Carlo
simulation approach was adopted to retain a high degree of flexibility in the model
structure so that mechanistic detail could easily be added and deleted as needed.
An additional benefit of this approach is its conceptual simplicity.
The model is driven by the following inputs: number of fish stocked each year,
number of years in which stocking occurs, a return schedule characteristic of the
species, statistical distributions for percentage return, percentage harvested, percentage straying (Table 5.1), and distribution of strays among streams (Table 5.2).
Model parameters were derived from data in the scientific literature, as explained
below. The model does not include natural production of smolts by returning
stocked fish.
Paul T. Jacobson
tions have since deteriorated. Attempts to reintroduce Atlantic Salmon earlier in
this century failed; however, Pacific Salmon were considered a feasible option
because they are more tolerant of water quality conditions to which they would be
exposed in the lower Delaware River.
The proposed program included monitoring of returning adults. Monitoring
was to begin 3 years after the first Chinook were stocked and to continue for 6
years after the last year of stocking. Elements of the monitoring/managerial program included marking or tagging of stocked fish, monitoring of movements of
returning adults, creation of a public awareness program, seasonal closure of the
lower Muscenetcong River, continuation of the statewide ban on snagging, and
collection of resource use and socioeconomic data. Because monitoring would
occur for at least 6 years beyond the last year of stocking, no action on a permanent program would occur for at least 11 years (Versar 1992a).
The experimental stocking and monitoring program was intended to provide
the information needed to assess the feasibility and advisability of a large-scale,
long-term program. If NJDFGW decided on the basis of the experimental program to proceed with a large-scale program, the data acquired from the monitoring program would be used to support a supplemental EIS.
Many of the potential environmental impacts identified by concerned citizens
during the NEPA issue scoping process derive from straying by returning salmon.
Examples of these impacts are colonization of streams, competition with native
and previously introduced salmonids in the upper Delaware River watershed, and
genetic depletion in a naturalized stock of Rainbow Trout in the upper Delaware
River basin. The level of risk associated with these concerns is related to the
probability and magnitude of straying. Thus, the risk assessment focused on
straying. The preferred species, Chinook Salmon, and two alternative species,
Coho Salmon and Steelhead Trout, were examined in the risk assessment.
Straying Model
Methods
Given the high degree of uncertainty and variability in factors that contribute to
straying, a probabilistic approach is a useful means of evaluating potential levels
of straying associated with stocking of anadromous salmonids. A Monte Carlo
simulation approach was adopted to retain a high degree of flexibility in the model
structure so that mechanistic detail could easily be added and deleted as needed.
An additional benefit of this approach is its conceptual simplicity.
The model is driven by the following inputs: number of fish stocked each year,
number of years in which stocking occurs, a return schedule characteristic of the
species, statistical distributions for percentage return, percentage harvested, percentage straying (Table 5.1), and distribution of strays among streams (Table 5.2).
Model parameters were derived from data in the scientific literature, as explained
below. The model does not include natural production of smolts by returning
stocked fish.