There are no robust, up-to-date assessments, nor basic information available, about incidental capture of ETP species in Guatemala’s mahi-mahi (dorado) longline fishery. Although minimum 5% observer coverage is required on longline vessels operating in the IATTC convention area (IATTC 2011a), it is rarely achieved by cooperating parties. This issue applies to the Guatemala mahi-mahi (or dorado) surface drifting longline fishery as well. However, Guatemala has no vessels larger than 20m in length, which is the minimum size of vessels to which current IATTC regulations on observer coverage and bycatch reporting apply (IATTC 2011). This fishery overlaps with several shark, seabird, marine mammal, and sea turtle populations, some of which are currently low abundance and declining, which means that numerically low bycatch interactions can still have significant population impacts (Lewison et al. 2014). There is no quantitative information available about ETP bycatch for this Guatemalan mahi-mahi longline fishery via any means of assessment (e.g., on-board observers, interview-based assessments).
Guatemalan longline fishing operations occur in a highly diverse area in terms of marine turtle regional management units (RMUs; (Wallace et al. 2010)), potentially overlapping with 5 different RMUs of two species, including Eastern Pacific leatherbacks, hawksbills, green turtles, and olive ridleys (arribada nesting RMU and solitary nesting RMU). Peak mahi-mahi fishing activities in Guatemala also apparently occur during peak sea turtle nesting season (September through March) (IATTC 2015). According to Lewison et al. (Lewison et al. 2004), longline fishing has contributed significantly to the decline of leatherback and loggerhead sea turtle populations in the eastern Pacific. These two species are both classified as Critically Endangered and Endangered, respectively (IUCN 2018). Pelagic longline fisheries are widely regarded as one of the main sources of fishing mortality for turtles (Lewison and Crowder 2007). However, there is exceedingly little data available on sea turtle interactions with Guatemalan dolphinfish fisheries (Hunter 2013). There are anecdotal reports of interactions with multiple sea turtle species including leatherbacks, olive ridleys, green turtles, and hawksbill, as well as seabirds (Stercorarius spp.) (CeDePesca 2013). According to CEDEPESCA (CEDEPESCA 2013), there are artisanal fleet reports regarding interactions between longlines and species like the green sea turtle (Chelonia mydas). The problem is that this information does not represent official statistical data. No assessment of the impacts of this fishery on turtle populations has been conducted (Hunter 2013).
There are several national laws that forbid the hunting of sea turtles and protect endangered species in compliance with CITES (National Strategy for Conservation of Sea Turtles; Protected Areas Law (Decree 4-89) and its regulations (Government Agreement 759-90); Resolution of the Executive Secretary of the National Council of Protected Areas number 048/2000). Guatemala’s longline fishery targeting mahi-mahi apparently uses circle hooks (although not mandatory), which can decrease the frequency and severity of sea turtle bycatch in many cases ((Andraka et al. 2013); (Swimmer et al. 2017)), but have varying effects on sharks and other bycatch species(Gilman et al. 2016).
As of 2012, there were an average of 90 longline vessels in Guatemala that were catching twenty times the number of sharks than mahi-mahi per year (>562,000 vs >23,000 individuals), and two-hundred times the number of sharks than yellowfin and skipjack tuna over a 12-year period through 2012 (>6,000,000 vs >37,000) (CeDePesca 2013)). Shark species reportedly retained in the Guatemalan longline fishery include: silky shark Carcharhinus falciformis, pelagic thresher Alopias pelagicus, common thresher Alopias vulpinus, bigeye thresher Alopias superciliosus, blacktip shark Carcharhinus limbatus, bull shark Carcharhinus leucas, oceanic whitetip shark Carcharhinus longimanus, shortfin mako shark Isurus oxyrinchus, scalloped hammerhead Sphyrna lewini, smooth hammerhead shark Sphyrna zygaena, blue shark Prionace glauca, and nurse shark Ginglymostoma cirratum (CeDePesca 2013).
Several of these species qualify as Endangered or Vulnerable (17 species overall; e.g., scalloped hammerhead, common and bigeye thresher sharks, silky shark) or Near Threatened (25 species overall; e.g., shortfin mako) in the East Central Pacific (Kyne et al. 2012). According to research by López (Lopez 2005), the scalloped hammerhead (Sphyrna lewini) represents 11% of the Guatemalan common dolphinfish bycatch in longline fisheries. There is no stock assessment for scalloped hammerhead in the Eastern Pacific, although this species is considered endangered (Kyne et al. 2012). IUCN also considers scalloped hammerhead as an Endangered species and describes that fishing pressure due to pelagic longline fleets is high and a significant decline of this species has been documented. There is also concern over the fact that some catches in some areas are comprised entirely of juveniles. On the other hand, IUCN also says that the larger hammerhead shark (Sphyrna mokarran) is assessed as Critically Endangered in this region from which it has apparently virtually disappeared. In Guatemala there is not enough information to establish and develop management measures for shark species taken as bycatch.
CEDEPESCA (CEDEPESCA 2013) has described that there was an interaction recognized between the common dolphinfish fishery and seabirds species belonging to the genus Stercorarius. However, the impact on their stocks has not been thoroughly assessed. Mangel et al. (Mangel et al. 2013) mentioned that in Central America, surveys in Guatemala had shown that pink-footed shearwater (Puffinus creatopus) is caught incidentally.
Several regional measures are in place for ETP species apply to Guatemala. Existing IATTC resolutions require best practices for safe release and handling of sea turtles captured in purse seines and longlines, as well as mitigation of ETP species including marine turtles (IATTC 2007), seabirds (IATTC 2011), mobulid rays (IATTC 2015), various shark species (IATTC 2016), and specific resolutions for silky sharks (IATTC 2016)) and oceanic whitetip sharks (IATTC 2011). The Organization of the Fisheries and Aquaculture Sector of the Central American Isthmus (OSPESCA) approved a common regional finning regulation that took effect in January 2012 for the eight member countries, including Guatemala, which requires sharks to be landed with their fins still naturally attached (Kyne et al. 2012).
In addition, Guatemala became a member party of the Inter-American Convention on the Protection and Conservation of Sea Turtles (IAC) in 2008; the IAC charter forbids retention of sea turtles in fisheries operations. The IAC also has several resolutions including measures to mitigate bycatch of sea turtles, for which annual reports on compliance are supposed to be provided each year, although they usually do not include estimates of the number of incidentally captured individuals. However, Guatemala’s 2018 annual report to the IAC indicated that information on sea turtle bycatch in Guatemalan fisheries is not generated because there is no observer program or other assessment method in place currently (IAC 2018).
The extent to which Guatemala is able to comply with these resolutions in unclear. A recent review highlighted several obstacles to good governance of Guatemala’s marine resources, i.e., environmental legislation is weak, fragmented and mediated across multiple actors and stakeholders, and institutional capacity is low (Gonzalez-Bernat and Clifton 2017).