In this report, the impacts of raising the minimum size limit from
11 inches (FL) to 12 inches (FL) in the Florida pompano fishery
were evaluated.
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Executive Summary
In this report, the impacts of raising the minimum size limit
from 11 inches (FL) to 12 inches (FL) in the Florida pompano
fishery were evaluated. It was assumed that the effects of all
other existing regulatory measures remained unchanged. A
catch-based projection and an equilibrium yield-per-recruit model
were used for evaluating the impact of the proposed 12-inch minimum
size limit on fishery yield and stock condition. These methods used
information on the fisheries landings and size composition data
reported for Florida pompano during 2006-09 from the Atlantic and
Gulf coasts of Florida. Biological data, size selectivity patterns,
and estimates of exploitation rates were also utilized for the
evaluation. The size-frequency data were generally sparse for the
2006-09 periods and mostly limited to the hook-and-line samples
from the commercial and recreational landings.
The proportion of the average total landings in the size
categories of 11-inch and smaller was fairly large, 45% on the
Atlantic coast and 40% on the Gulf coast during 2006-09. The
catch-based projection runs predicted that the annual landings of
Florida pompano could potentially drop between 12% and 24% on the
Atlantic coast and drop between 10% and 21% on the Gulf coast with
the implementation of the 12-inch minimum size limit under four
different compliance rates (85%, 90%, 95%, and 100%). The projected
annual landings reductions for 85% compliance were 12% on the
Atlantic coast and 10% on the Gulf coast. The stock abundance of
Florida pompano was predicted to increase by 19% on the Atlantic
coast and 14% on the Gulf coast under the 85% compliance rate.
Results from the length based yield per recruit analysis show
that, at current levels of fishing mortality, raising the minimum
size limit from 11 inches FL to 12 inches FL in the Florida pompano
fishery, will result in an increase in the spawning biomass per
recruit (SB/R) on both coasts of Florida. The SB/R was predicted to
increase by 29% on the Atlantic coast and by 18% on the Gulf coast
based on the ascending selectivity pattern. Slightly higher gains
were estimated for the SB/R from the model runs with a knife-edge
selectivity pattern. Estimates of the Spawning Potential Ratio
(SPR) for different combinations of size-at first capture (minimum
size limits) and fishing mortality rates showed 1) The SPR
increased with increase in minimum size limit; and 2) the risk of
the SPR dropping below 20% was reduced significantly under the
12-inch minimum size limit if the fishing mortality increased above
the existing rates.
Results from these analyses must be
viewed with caution. The size composition data used in the
catch-based projections were limited mostly to the hook-and-line
fishery low sample sizes. There was little size information
available from the commercial gill-net fishery, which constitutes a
large proportion of the total landings on the Gulf coast. A number
of simplifying assumptions were made: 1) no stock-recruitment
feedback was included in the projections; 2) models assumed
constant fishing catchability and selectivity; 3) model projections
did not include potential effects of other management measures
(e.g., bag-limit, commercial vessel limit) already in place in the
pompano fishery; and 4) the analysis assumed no interplay between
the minimum size limit and other management measures in place in
the fishery.
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