INTERACTIONS WITH FISHERY

 

 

Illuminated handlines for squids

Surface longlines

Trawling nets

Bottom gillnets

Driftnets

 

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Interactions with fishery were recorded in the area with illuminated handlines for squids, surface longlines, trawling nets, bottom gillnets and drift nets.

 

HANDLINES FOR SQUIDS

Interactions occurred with striped dolphins, Risso's dolphins, long finned pilot whale and sperm whale. In all cases an opportunistic feeding was completed by small groups (of 2-5) or single animal (sperm whale); cetaceans waited near the fishing boats until gear's light had attracted a great number of squids under the boats and then they quickly swam to catch their prey; this technique may be repeated several time in one night.

 

SURFACE LONGLINES

Interactions were recorded with sperm whale and Risso's dolphin. Animals were found entangled in abandoned gears, probably drowned in the course of capturing their prey.

 

TRAWLING NETS

Trawlers are not requested to comply with the regulations intended to prevent overfishing, therefore producing clear environmental damage.
A recent review by Buia et al. (2003) reported a remarkable alteration in the structure of Neptunegrass (Posidonia oceanica) beds, related to the illegal and uncontrolled trawling. Neptunegrass beds - distributed all around the island of Ischia up to about 30 m of depth - have been monitored since 1975. Terlizzi (1991) analysed the fauna associated to the leaf stratum and found a notable diminution in biomass value in 1988-89, as compared to 1981-1982, as well as an important reduction of biodiversity. Finally, a general survey around the hard bottoms of Ischia conducted by Gambi et al. (2003) showed that fish stocks are generally scarce and dominated by non-commercial species.

Interactions were recorded with striped and bottlenosed dolphin, in both cases involving an opportunistic feeding by small groups (of 2-5): making long dives, dolphins fed all around and within the net especially at the end of the haul.

 

BOTTOM GILLNETS

Bottom gillnets are used in the area only by artisanal fishermen. Around the island of Ventotene and Ischia, interactions were recorded with bottlenosed dolphins: every year, in the months of March, May and September they were observed preying from the nets. Dolphins made long dives around the net, and produced large rips to catch their prey.

 

ILLEGAL, UNCONTROLLED AND UNREGULATED DRIFNETTING

Several cetaceans and other marine species are known to have been entangled in driftnets, reaching unsustainable bycatch rates.
In the Mediterranean Sea, driftnet fishery is largely diffused in Italy, where both nets and vessels are usually called "spadare". Swordfish (Xiphias gladius) and albacore (Thunnus alalunga) are the targeted species.
The gear is characterized by a large mesh (range: 15-50 cm) with positive buoyancy (floating), a length of about 15 km and a high of 15-30 m. The net is usually set at the sunset in a "S" or zig-zag pattern.

This peculiar fishing technique is highly dangerous for the pelagic fauna, with an immediate and devastating impact. Spadare's victims include small Odontocetes species, large whales as sperm whale (Physeter macrocephalus), and other marine animals like moon fish (Mola mola), manta (Mobula mobular), sharks, sea turtles (Caretta caretta) and some species of seabird.
On January 1st, 2002, EU ban on all driftnetting fisheries; notwithstanding, fishing activities with driftnets persist in some Italian waters as an illegal practice. In order to stop unlawful actions, Italian Government started a conversion plan aiming to shift from spadare to trawlers or purse seiners, providing fishermen with indemnity funds (DM 25/7/2002).
Nevertheless, a "small" pelagic driftnet (called "ferrettara") with a mesh of 15 cm of side) and a length of 2 Km was introduced by the Italian legislator (D.M 14.10.1998 n.281) and recently reconsidered by the Italian Fishery Ministry, receiving an ambiguous decree (DM 4/4/2003) that allows fishermen (even those who benefited from the EU conversion plan and received indemnity funds) to embark ferrettare and anchored gillnets of a maximum length of 5 km. Such new licenses produced unrestrained fishing activities since vessels embarked some different kind of nets (not only ferrettare and anchored gillnets).
Control each boat is virtually impossible. Authorities have to verify the type of the net onboard, the length and, potentially, the way in which they are used at sea. After one year from the decree DM 4/4/2003, enforcement is poor and impact data on cetacean species are not available.

Notwithstanding the EU band on the driftnetting fishery, started on January 1st, 2002, illegal fishing with drftnets is still a problem around the Island of Ischia. Swordfish boats equipped with driftnets were monitored in the area since May 2003, but only during periods of sea storm it has been possible to count the boats operating in the region. We recorded a total of 37 boats (15-30 m long) equipped with driftnets. Several boats had modified the sides of their vessels to hide the nets carried on board, making it difficult to evaluate the volume of visible coils on the deck. Boats were mainly from Calabria, but also from Sicily and Ischia, whereas other boats exhibited no registration code.

It was possible to documented swordfishes landing, with a total of 237 swordfishes and 73 tuna observed. All these catches (with the use of the nets) are forbidden by the Reg. (CE) 1239/98. Swordfishes were carried on three trucks, two of them showing the EU logo.

Striped dolphins and sperm whales were found stranded or adrift around Ischia with body mutilations and lesions indicative of bycatch in driftnets. One specimen had had its flukes and dorsal fin cut off, and had been tied with a rope around its pectoral fins and head.

The geomorphology of the study area, including productive submarine canyons, makes it an attractive area for a number of cetacean species cetaceans. In particular, the waters of Ischia have been classified as a critical habitat for endangered short-beaked common dolphins (www.redlist.org) in the recent IUCN Cetacean Action Plan (Reeves et al. 2003, see www.iucn.org/themes/ssc/news/cetaceansap.htm) and represent an important feeding and breeding ground for cetacean species including the fin whale.