content: text: There is no question that fishing is the major factor driving
grouper stocks on the downward spiral, but those that have
large spawning aggregations are most vulnerable to declines
(Coleman et al. 1996; Asch and Erisman 2018; Sadovy de
Mitcheson et al. 2020). Because it takes a long time for
scientists to obtain needed life history information, fisheries-
independent survey data, and catch history, grouper
populations may be overfished long before data are even
available for a stock assessment. Without formal stock
assessments, general indicators of population status are
based on catch trends. Very few grouper stocks that have
spawning aggregations are managed sustainably. In a recent
global analysis of the status of populations that form
spawning aggregations, 45% were unknown, 33% were
decreasing, and 5% were already gone (Figure 13.5). Only 12%
had stable populations, and 5% were increasing.

content: text: Gone
Increasing
5%
5%
Same
12%
Unknown
45%
Decreasing
33%

content: text: Figure 13.5: Current known status reflecting changes
of exploited grouper aggregations globally, as noted by
fisher interviews, monitoring, or underwater surveys
(N = 509). Long description.

content: text: Of the 167 species of grouper, 9.6% are vulnerable, 4.8% are near threatened, 1.2% are endangered, and 0.6%
are critically endangered (Figure 13.6). The majority of species (68.9%) are classified as least concern and 15%
are data deficient, with insufficient data for classification. The larger (>50 cm total length) and long-lived (>20
years) species of grouper that also had smaller geographic ranges were most likely to be endangered or critically
endangered (Luiz et al. 2016). Market prices for grouper are escalating, and other lower-valued fish are often
mislabeled or substituted.

content: text: Critically Endangered
endangered 1%
Vulnerable
1%
Data deficient 9%
15%
Near
threatened
5%
Least concern
69%

content: text: Figure 13.6: Categories of all grouper species (N = 167)
according to the IUCN Red List (IUCN Red List
Assessments, updated November 2018). Long description.

content: text: To protect grouper from overfishing, many measures are
being implemented, such as minimum and slot-size
limits, recreational bag limits, commercial fishing quotas,
gear and seasonal controls, marine protected areas, and
limited entry (Rocklin et al. 2022). The effectiveness will
depend on traits of the species and the local context.
Regulations to prevent marketing of undersize fish will
mitigate growth overfishing. Allowing smaller fish to
reach maturity at least once before harvest will mitigate
recruitment overfishing. Size-limit regulations focused
on protecting spawning-size fish may be ineffective for
deepwater recreational fishing. Grouper have a
physoclistous (i.e., closed) swim bladder, making them
particularly susceptible to ruptured swim bladders,
bloating, stomach distention, and protruding eyes caused
by rapid decompression when hauled to the surface
(Brule et al. 2015). The proportion of grouper with
distended stomachs was 70% in one study of commercial
hook-and-line fishing and as high as 95% for Red

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