275
8 Fishery and Biological Implications of Fishing Spawning Aggregations…
from St. Croix, USVI, gave mixed responses as to whether they felt that a newly
expanded area more effectively protected an aggregation site than existing area/
season protection and gave them benefi ts. The general sense was that they did not
fully understand the purpose of the additional protection and also felt that poaching
was occurring because of insuffi cient enforcement and unclear boundaries to the
protected area. There was also lack of clarity over perceived benefi ts of the seasonal
closure, possibly due to slow recovery, and concern over economic hardship from
the measures (Karras and Agar 2009 ) . This study, and other experiences following
management, demonstrates the importance of effective enforcement, communication with, and involvement of, fi shers in planning, and monitoring of management
outcomes. More studies on fi sher perceptions are needed.
8.8 Concluding Comments
The habit of congregatory spawning is found in many species of fi sh from different
ecosystems, in addition to coral reefs, and is common among commercial species.
Indeed, it may be that the aggregating habit characterizes many exploited species
expressly because it is a reproductive strategy associated with high productivity.
If so, it is perhaps ironic that it is the aggregating habit that makes many such species particularly vulnerable to uncontrolled fi shing.
Understanding the implications of overfi shing or of eliminating aggregations is
frustrated by insuffi cient information and by our lack of understanding regarding
why aggregations have evolved. Empirical data from aggregations at different
stages of exploitation and in relation to the populations they support are needed.
From a biological perspective, there is much opportunity to incorporate elements
of fi sh mating systems into fi shery models to generate different scenarios against
which to assess observations and make predictions or conduct comparative assessments. For example, if sperm competition is important for group-spawners and is
negatively affected by declining fi sh numbers or sex-selective fi shing, then one
might predict that such species might show more marked declines than non groupspawning species. What are the effects of reduced aggregation sizes on reproductive activity and is there a minimum threshold size below which spawning ceases
to occur? We might predict that transient aggregations are more vulnerable to
targeted aggregation fi shing than resident aggregators. From an economic perspective, are there more long-term benefi ts from fi shing outside of aggregations and
avoiding the possible waste and reduced prices associated with fi shing gluts of
spawning fi sh?
Turning to management, answers to the preceding questions should point the
way to better determining the most effective and acceptable approach(es) to managing different types of aggregating species, and whether management of aggregations is necessary, in addition to management measures on target stocks (Chap. 11 ).
Furthermore, valuable insights gained as we learn more of these species point to
other important considerations. As just one example, it is clear that many transient
8 Fishery and Biological Implications of Fishing Spawning Aggregations…
from St. Croix, USVI, gave mixed responses as to whether they felt that a newly
expanded area more effectively protected an aggregation site than existing area/
season protection and gave them benefi ts. The general sense was that they did not
fully understand the purpose of the additional protection and also felt that poaching
was occurring because of insuffi cient enforcement and unclear boundaries to the
protected area. There was also lack of clarity over perceived benefi ts of the seasonal
closure, possibly due to slow recovery, and concern over economic hardship from
the measures (Karras and Agar 2009 ) . This study, and other experiences following
management, demonstrates the importance of effective enforcement, communication with, and involvement of, fi shers in planning, and monitoring of management
outcomes. More studies on fi sher perceptions are needed.
8.8 Concluding Comments
The habit of congregatory spawning is found in many species of fi sh from different
ecosystems, in addition to coral reefs, and is common among commercial species.
Indeed, it may be that the aggregating habit characterizes many exploited species
expressly because it is a reproductive strategy associated with high productivity.
If so, it is perhaps ironic that it is the aggregating habit that makes many such species particularly vulnerable to uncontrolled fi shing.
Understanding the implications of overfi shing or of eliminating aggregations is
frustrated by insuffi cient information and by our lack of understanding regarding
why aggregations have evolved. Empirical data from aggregations at different
stages of exploitation and in relation to the populations they support are needed.
From a biological perspective, there is much opportunity to incorporate elements
of fi sh mating systems into fi shery models to generate different scenarios against
which to assess observations and make predictions or conduct comparative assessments. For example, if sperm competition is important for group-spawners and is
negatively affected by declining fi sh numbers or sex-selective fi shing, then one
might predict that such species might show more marked declines than non groupspawning species. What are the effects of reduced aggregation sizes on reproductive activity and is there a minimum threshold size below which spawning ceases
to occur? We might predict that transient aggregations are more vulnerable to
targeted aggregation fi shing than resident aggregators. From an economic perspective, are there more long-term benefi ts from fi shing outside of aggregations and
avoiding the possible waste and reduced prices associated with fi shing gluts of
spawning fi sh?
Turning to management, answers to the preceding questions should point the
way to better determining the most effective and acceptable approach(es) to managing different types of aggregating species, and whether management of aggregations is necessary, in addition to management measures on target stocks (Chap. 11 ).
Furthermore, valuable insights gained as we learn more of these species point to
other important considerations. As just one example, it is clear that many transient