Protected Species and Marine Aquaculture Interactions

northeast and southwest were not available. Croxall et al. (2012) conclude that more than
80 species of coastal and pelagic seabirds are threatened by mortality in fishing gear, and
identify continued bycatch reduction as a priority management need.
Bycatch of seabirds in gillnets is known to occur through entanglement in the netting
(Hall and Mainprize 2005, Løkkeborg 2011). Warden (2010), reports that from
1996– 2007, the average annual gillnet bycatch in the northeast was 74 common loons
Gavia immer, and in the Mid-Atlantic annual estimates are 477 common and 897 redthroated
loons G. stellate. The red-throated loon is a species of conservation concern,
and these mortality estimates reflect about 60% of the Potential Biological Removal
(PBR) levels. Žydelis et al. (2009) estimated that coastal gillnet fisheries in the Baltic
and North Seas may catch more than 90,000 seabirds per year. A global review of
seabird bycatch suggests as many as 400,000 birds may die in gillnets annually (Žydelis
et al. 2013). At a recent workshop to address bycatch reduction of marine life, proposed
methods to decrease seabird bycatch in gillnets included net striping, pingers,
high-visibility net sections, lighting and dropped headlines (Wiedenfeld et al. 2015).
Because bycatch reduction approaches for longlines often seek to reduce hooking (Hall
and Mainprize 2005, Lewison et al. 2004, Løkkeborg 2011), there may be few applications
to aquaculture gear. Trawl fisheries bycatch primarily tends to involve collision
with towing cables (Løkkeborg 2011), which is also dissimilar to gear at aquaculture facilities,
but can also result from entanglement in trawl netting.
Løkkeborg (2011) provides an overview of measures that have been tested in longline,
trawl and gillnet fisheries, and reviews their fishery suitability and efficiency in
mitigating bycatch of seabirds. He notes that bycatch reduction can be extremely effective,
often reducing bycatch by more than 80% with little impact to target catch rates.
This conclusion is supported by NMFS data from Alaska and Hawaii where significant
reductions in seabird bycatch were achieved through collaborations with fishing industry
groups, gear technologists, scientists, seabird biologists, and environmental conservation
groups (NMFS 2008a). Though the primary trust responsibilities for seabirds
lies within the USFWS, NMFS recognizes seabirds are ecosystem indicators and a vital
part of healthy ocean ecosystems. Therefore, NMFS is concerned about the long-term
ecosystem effects of seabird bycatch in fisheries, and managing the marine habitats that
seabirds depend on within the U. S. EEZ (Rivera et al 2014, NMFS 2014b).
Ensuring that no
feed, live FIsh or
carcasses are
released from
farm vessels
during stocking,
transport or
harvest should
decrease
attraction of
farm vessels to
marine animals
opportunistically
seeking food
sources.
Vessel Strikes
Another large source of injury and mortality to marine species is vessel strikes (Waring
et al. 2012, 2015). Marine aquaculture facilities inherently require the use of
small and large vessels to transport materials, fish, feed, harvesting equipment, and
maintenance crews between farm sites and shore. This vessel traffic could also potentially
impact protected species and is considered in permit review and consultations.
Ensuring that no feed, live fish or carcasses are released from farm vessels during
stocking, transport or harvest should decrease attraction of farm vessels to marine
animals opportunistically seeking food sources.
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