Cease or prohibit spearfishing
Overall effectiveness category Awaiting assessment
Number of studies: 5
Background information and definitions
Spearfishing is a technique of hunting fish underwater, historically with sharpened or barbed sticks, but in current times often using powered metal spearguns. Spearfishing is done by free diving, snorkelling or scuba diving and is one of the few fishing techniques where each target fish is individually selected, and unwanted catch is virtually nil. However, spearfishing is widely used, is an effective and efficient method of harvesting fish and activities may be concentrated at habitats such as reefs. In heavily targeted areas, local fish populations can be severely depleted (Dulvy & Polunin 2004; Godoy et al. 2010) or may suffer other impacts related to the removal of particular sizes or sexes of fish (Alonzo & Mangel 2004). Spearfishing activity is managed throughout the world with a wide range of restrictions ranging from complete bans to prohibiting the use of scuba or spearguns or allowing only recreational spearfishing. Prohibiting spearfishing may often be implemented in marine protected areas with the aim of preventing localised overfishing or selective removal of parts of the fish population.
Alonzo S.H. & Mangel M. (2004) The effects of size-selective fisheries on the stock dynamics of and sperm limitation in sex-changing fish. Fishery Bulletin, 102, 1–13.
Dulvy N. & Polunin N. (2004) Using informal knowledge to infer human-induced rarity of a conspicuous reef fish. Animal Conservation, 7, 365–374.
Godoy N, Gelcich S., Vasquez J.A. & Castilla J.C. (2010) Spearfishing to depletion: evidence from temperate reef fishes in Chile. Ecological Applications, 20, 1504–1511.
Supporting evidence from individual studies
A review in 1993 of studies of reef marine reserves (Roberts & Polunin 1993) reported that prohibiting spearfishing in two areas in the north Atlantic Ocean/Gulf of Mexico, off the Florida Keys, USA, resulted in increased abundance of targeted snappers and grunts (species not given) two years after closure, and higher densities and larger lengths of several reef fish, including snappers and grunts after 20 years, compared to nearby fished reefs. Two years after spear fishing was prohibited, abundance of snappers and grunts at Looe Key Reef marine sanctuary increased by 93% and 439% respectively, and in addition, several previously absent species also appeared in the prohibited area which were rare in fished areas. Data for the densities and lengths of reef fish in the Key Largo National Marine Sanctuary 20 years after spearfishing was prohibited were not provided. Eleven case studies of reef marine reserves across the world were reviewed (search/selection method not reported); two had evidence for the effects of prohibiting spearfishing.Study and other actions tested
A site comparison study in 1995 of coastal waters in the Mediterranean Sea, southwestern France (Jouvenel & Pollard 2001) found that prohibiting spearfishing in a marine reserve for an unknown number of years, resulted in higher abundance and greater length of European seabass Dicentrarchus labrax and higher abundance of gilthead seabream Sparus aurata, compared to unprotected fished areas. Average abundance of both species was higher inside the reserve (seabass: 3.9 fish/400 m, bream: 0.7 fish/400 m) than outside (seabass: 0.7 fish/400 m, bream: 0.1 fish/400 m). Average length of seabass was higher inside the reserve (381 mm) compared to outside (212 mm). In addition, average length of gilt head bream was lower inside the reserve (379 mm) than outside (400 mm), but this was not tested statistically due to low sample size outside of the reserve. Data were collected in July 1995 over 26 km of coastline with varied habitat types from Cape Bear to Terrimbau Bay. In the centre is the Banyuls-sur-Mer marine reserve (10 km), where spearfishing was banned throughout (year implemented not reported), but other fishing practices were allowed. Snorkellers counted and recorded lengths of all seabass and gilthead bream along 64 transects of 400 m within 5 m of the shore.Study and other actions tested
Referenced paperJouvenel J.Y. & Pollard D.A. (2001) Some effects of marine reserve protection on the population structure of two spearfishing target-fish species, Dicentrarchus labrax (Moronidae) and Sparus aurata (Sparidae), in shallow inshore waters, along a rocky coast in the northwestern Mediterranean. Aquatic Conservation: Marine and Freshwater Ecosystems, 11, 1-9.
A site comparison study in 2002–2004 of four rocky reef areas in the Tasman Sea, New South Wales, Australia (Curley et al. 2013) found that prohibiting spearfishing inside a marine protected area for 10–12 years resulted in differences in the overall density of targeted reef fishes on shallow but not deep reefs, and individual differences in density were found for only two of seven fish species/groups compared to unprotected reference areas, and the effect varied with fish size. The densities of all sizes of commonly harvested fish differed between protected and non-protected areas at shallow but not deeper depths (data reported as statistical results). Abundance of legal sized (>200 mm), but not small red morwong Cheilodactylus fuscus was higher inside the reserve than outside at both shallow (1.3 vs 0.3/200 m2) and deep (2.8 vs 1.2/200 m2) reefs, and abundance of legal-sized (>200 mm) yellowfin bream Acanthopagrus australis was higher inside than outside at shallow reefs (0.7 vs 0.3/200 m2) but similar at deep reefs (0.2 vs 0.1/200 m2). There were no effects of protection on densities of five other groups (see paper for details of groups), but there were differences with depth and sampling time (data reported as statistical models). Spearfishing was banned in January 1992 at the Gordons Bay area (0.1 km2) of the Bronte-Coogee Aquatic Reserve. Recreational line fishing and collection of rock lobsters and bait weed were permitted but eastern blue groper Achoerodus viridis may not be taken by any method. Between November 2002–2004, fish were sampled six times by underwater visual census at one location within the reserve and three reference areas outside (10–80 km away). At each location and at two depths (<3.5 m and 4–12 m), five replicate 40 × 5 m transects were surveyed.Study and other actions tested
A site comparison study in 2006–2011 of four coral reef sites in a marine protected area in the Indian Ocean, South Africa (Maggs et al. 2013) found higher abundance and larger size of four coral reef fish species in a zone closed to offshore (vessel-based) spearfishing and all other vessel-based fishing, compared to edge zones where only offshore spear and line fishing is permitted. Individual catch rates were higher inside the no-take zone than the fished zone for all four species in each year: slinger Chrysoblephus puniceus (3.1 vs 0.8 fish/angler/h), Scotsman Polysteganus praeorbitalis (1.2 vs 0.3 fish/angler/h), poenskop Cymatoceps nasutus (0.4 vs 0.2 fish/angler/h) and yellowbelly rockcod Epinephelus marginatus (0.6 vs 0.1 fish/angler/h), and average lengths were also higher (slinger: 293 vs 240, Scotsman: 415 vs 359, poenskop: 417 vs 380, rockcod: 495 vs 435 mm). In addition, three of the four species (slinger, Scotsman, rockcod) showed increases in size over time (data not tested statistically). The Pondoland Marine Protected Area (800 km2) was designated in 2004 and comprises a central ‘no-take area’ (400 km2) closed to all offshore (vessel based) exploitation. On either side of the no-take zone are two controlled fishing areas where offshore line fishing and spearfishing are permitted. No commercial fishing, such as trawling or long-lining, is permitted anywhere in the protected area. From April 2006 to June 2011, quarterly research angling was conducted at two sites in the no-take zone and two in the nearby exploited zone (6 h angling in each zone) at 10–30 m depth. Data were analysed for four species depleted by line fishing.Study and other actions tested
A replicated, site-comparison study in 2000–2012 of mixed bottom (rock, sand and seagrass Posidonia oceanica) areas inside and outside a marine reserve in the Mediterranean Sea, off Corsica (Marengo et al. 2015) found that catch rates of common dentex Dentex dentex targeted by two different fishery types were higher in zones where spearfishing was prohibited for one to three years, compared to a zone that allowed it and/or areas outside the reserve. For the artisanal fishery (small commercial boats), average catch rate differed between all three zones and was highest in the no spearfishing zones (no spearfishing: 99, general: 17, outside: 26 g/50 m net). For recreational fishing activity, average catch rate in the no spearfishing zones was higher compared to the general zone (no spearfishing: 355, general: 56 g/50 m net) (no catch data outside). Bonifacio Strait Natural Reserve (79, 640 ha) was created in 1999 and has four partially protected zones (each encompassing no-take zones) where spearfishing is prohibited but small-scale artisanal (mainly trammel nets and longlines) and other recreational fishing (mainly longlines and hook and line) is permitted. In the rest of the reserve (general zone) spearfishing is allowed. A total of 962 commercial artisanal boats were sampled May-July 2000 to 2012 (except 2009) onboard or on landing, and 459 recreational boats between March-October in 2006, 2008, 2011. Retained dentex catch was recorded by zone fished (inside reserve: partially protected and general zones, and outside reserve), gear type, and fishing effort.Study and other actions tested