80 FR 36974 - Stock Status Determination for Atlantic Highly Migratory Atlantic Smooth Dogfish Shark and the Gulf of Mexico Smoothhound Sharks Complex

DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration

Federal Register Volume 80, Issue 124 (June 29, 2015)

This action serves as a notice that NMFS, on behalf of the Secretary of Commerce (Secretary), has determined that the Atlantic smooth dogfish shark (Mustelus canis) and the Gulf of Mexico smoothhound shark complex, which is comprised of Atlantic smooth dogfish, Florida smoothhound (M. norrisi), and Gulf smoothhound (M. sinusmexicanus), are not overfished and overfishing is not occurring.

[Federal Register Volume 80, Number 124 (Monday, June 29, 2015)]
[Notices]
[Pages 36974-36975]
From the Federal Register Online  [www.thefederalregister.org]
[FR Doc No: 2015-15809]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

RIN 0648-XD969


Stock Status Determination for Atlantic Highly Migratory Atlantic 
Smooth Dogfish Shark and the Gulf of Mexico Smoothhound Sharks Complex

AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and 
Atmospheric Administration (NOAA), Commerce.

ACTION: Notice.

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SUMMARY: This action serves as a notice that NMFS, on behalf of the 
Secretary of Commerce (Secretary), has determined that the Atlantic 
smooth dogfish shark (Mustelus canis) and the Gulf of Mexico 
smoothhound shark complex, which is comprised of Atlantic smooth 
dogfish, Florida smoothhound (M. norrisi), and Gulf smoothhound (M. 
sinusmexicanus), are not overfished and overfishing is not occurring.

FOR FURTHER INFORMATION CONTACT: Andrew Rubin or Karyl Brewster-Geisz 
by phone at 301-427-8503.

SUPPLEMENTARY INFORMATION: 

Background

    Atlantic smooth dogfish, Florida smoothhound, and Gulf smoothhound 
sharks are managed under the authority of the Magnuson-Stevens Fishery 
Conservation and Management Act. NMFS manages all shark species, except 
for spiny dogfish (Squalus acanthias), under the 2006 Consolidated 
Atlantic Highly Migratory Species (HMS) Fishery Management Plan (FMP) 
and its amendments.
    NMFS recently assessed the status of these species for the first 
time using the Southeast Data, Assessment, and Review (SEDAR) process. 
The final stock assessment (SEDAR 39) was finalized and peer reviewed 
in March 2015.
    Data from tagging and genetic research in SEDAR 39 support the 
existence of two distinct Atlantic and Gulf of Mexico stocks of smooth 
dogfish separated by peninsular Florida. Therefore, smooth dogfish was 
treated as two separate stocks, one in the Atlantic region and one in 
the Gulf of Mexico region.
    Additionally, because smooth dogfish are the only species of 
smoothhound sharks occurring in the Atlantic region, the scientists 
conducted a stock assessment for only this species in the Atlantic 
region. However, because all three species occur in the Gulf of Mexico, 
and given the difficulty with distinguishing among and identifying the 
individual species of smoothhound sharks occurring in the Gulf of 
Mexico region, the scientists treated all three smoothhound species 
(smooth dogfish, Florida smoothhound, and Gulf smoothhound) as a single 
smoothhound shark complex within the Gulf of Mexico region.
    All documents and information regarding SEDAR 39 can be found on 
the SEDAR Web page at http://sedarweb.org/sedar-39.

Atlantic Region

    For Atlantic smooth dogfish, the scientists used a length-based 
age-structured stock assessment model. This was the first HMS shark 
stock assessment conducted within the SEDAR process to utilize this 
type of modeling framework. The Atlantic smooth dogfish assessment 
implemented spawning stock fecundity (SSF), which was used as a proxy 
for biomass, natural mortality (M), steepness of the Beverton-Holt 
stock-recruitment relationship, and the selectivity patterns using the 
same methods as in previous HMS shark assessment.
    Two selectivity patterns were explored for the main targeted 
gillnet fishery (dome-shaped and asymptotic). The use of these two 
selectivity patterns resulted in two alternative base model 
configurations being evaluated. Based on diagnostic results, the 
scientists recommended that the dome-shaped functional form be selected 
as the base model. The peer reviewers found this base model to be an 
appropriate methodology.
    For this base model, the stock assessment scientists explored seven 
sensitivity scenarios. All seven model runs found that SSF in 2012 
(SSF2012), was greater than SSFMSY 
(SSF2012/SSFMSY ranged from 1.96 to 2.81 vs. 2.29 
in the base model) and that F2012 was less than 
FMSY (F2012/FMSY ranged from 0.61 to 
0.99 vs. 0.79 in the base model). Projection results for the base model 
configuration indicated that levels of fixed removals less than or 
equal to 550 (1000s of sharks) resulted in at least a 70 percent 
probability of maintaining SSF above SSFMSY during the years 
2013-2022. Projections for the seven sensitivity scenarios resulted in 
a range of fixed removals from 350 to 850 (1000s of sharks) with at 
least a 70 percent probability of maintaining SSF above 
SSFMSY during the years 2013-2022.
    The peer reviewers found it is likely that the Atlantic smooth 
dogfish stock is not overfished, and overfishing is not occurring based 
on the base model and range of associated sensitivities. The peer 
reviewers indicated that the range of sensitivities appropriately 
captured the uncertainty regarding the states of nature and the 
potential implications for the reference points. However they cautioned 
about inferences drawn about stock status because of the level of 
uncertainty associated with the stock-recruitment relationship and 
uncertainty in the catches, and noted that the fishing level for the 
most recent year is close to FMSY for some sensitivity runs. Overall, 
the peer reviewers determined the stock assessment to be based on the 
best scientific information available. Based on these results, NMFS 
determined that the status of smooth dogfish is not overfished and 
overfishing is not occurring.

Gulf of Mexico Region

    The model structure for the Gulf of Mexico smoothhound shark 
complex was different than the Atlantic stock of smooth dogfish because 
of the need to combine life history data for all three

[[Page 36975]]

species. The scientists combined this data using a life table to 
calculate the mid-point biological values between the species. They 
then used a state-space Bayesian surplus production model that 
implemented a Schaefer production model in a Bayesian framework. The 
peer reviewers found this model to be appropriate and robust. The 
reviewers noted issues could occur if the biology and population 
dynamics differed significantly but they did not believe this was an 
issue for the current assessment.
    In addition to the base model, the assessment scientists ran a 
number of sensitivities. All sensitivities found that the number of 
sharks in 2012 (N2012), which was the proxy used for biomass 
for this model, was greater than NMSY (N2012/
NMSY ranged from 1.68 to 1.83 vs. 1.78 in the base model) 
and the exploitation rate in 2012 (H2012), which was the 
proxy used for fishing mortality in this model, was less than 
HMSY (H2012/HMSY ranged from 0.07 to 
0.35 vs. 0.18 in the base model). Projections under varying catch 
levels conducted with the base model and sensitivities reflecting 
plausible states of nature, except the low catch scenario which was not 
deemed plausible, indicated that the 2012 catch could be increased by a 
factor of 4 and still allow for less than a 30 percent probability of 
the stock being overfished during any of the 10 years in the projection 
horizon. Similarly, the projected scenarios indicated that the 2012 
catch could be increased by a factor of 2, 3, or 4 and still allow for 
less than a 30 percent probability of overfishing occurring during any 
of the 10 years in the projection horizon.
    The peer reviewers found the Gulf of Mexico smoothhound complex is 
most likely neither overfished, nor undergoing overfishing. The peer 
reviewers noted that the reliability of the stock status determination 
is dependent on the accuracy of the shrimp trawl bycatch estimates for 
these species and suggested that NMFS explore alternative catch streams 
to help assess this uncertainty. Nonetheless, the review panel believed 
that the model and associated sensitivities captured the main 
uncertainties associated with the assessment. The review panel 
considered the base model and corresponding sensitivity runs the best 
scientific information available. Based on these results, NMFS 
determined that the status of the Gulf of Mexico smoothhound shark 
complex is not overfished and overfishing is not occurring.

    Dated: June 23, 2015.
Jennifer M. Wallace,
Acting Director, Office of Sustainable Fisheries, National Marine 
Fisheries Service.
[FR Doc. 2015-15809 Filed 6-26-15; 8:45 am]
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