**2. Protecting vulnerable elasmobranch species: targeting marine biodiversity conservation**

In the Mediterranean, elasmobranches account for less than 1.5% of the total fish landings in the area [4], therefore their economic importance is much lower than that of teleosts, nonetheless they have an important socio-economic role in Mediterranean fisheries [2, 22, 23].

On a global scale, elasmobranch landing records have shown drastic reduction for several species, with global negative population trends. This has led to a growing list of elasmobranch species within the high risk conservation categories of the IUCN Red List, with overfishing being the main threat for the declining stocks [24–31].

At a Mediterranean level, the total number of elasmobranch species inhabiting the region adds up to around 80 [26, 27, 30, 32, 33]. A number of these species have a worse conservation status within the Mediterranean, when compared to their global conservation status since this region is highly populated with evergrowing coastal communities, fishing activities and maritime services, leading to increased pressure on the existing elasmobranch populations, their prey and habitats [27, 28, 30, 31, 34]. In the Mediterranean Sea, higher risk is further exacerbated by limited migration between populations within and outside the region [31, 35].

Despite the increased vulnerability, there are no official records of chondrichthyes that have been totally extirpated from the Mediterranean [27, 28, 31] although there has been a significant decline in their landings both in terms of biomass and numbers, and it is known that some species have disappeared from certain areas [26, 28, 36, 37]. The European landing records for Mediterranean chondrichthyes recorded a decline of around 60% between 1994 and 2004, namely due to declining stocks [4, 27, 30, 31]. These factors together with incomplete knowledge about their fisheries, trophic linkages and species specific life-history data make it really difficult to pinpoint the first warning signs of stock decline, making these top predators more vulnerable to anthropogenic activities, which impose both direct and indirect pressures to their survival. However, these threats, not only affect the survival of the species, but also the livelihood of small-scale fishermen who for decades have earned their living from these marine resources.

Urgent and in depth assessment of the impacts of currently adopted and prospective regulations is needed. Such assessment has to look into the effectiveness and problems of fisheries regulations on the welfare of both local marine biodiversity and local fishers. For this reason, the CBRG-UoM, has been sustaining long-term research on artisanal fishing activities in Malta since 1998, identifying the need for greater collaboration between fishers, fishing authorities and independent researchers that would bring about the necessary scientific information on fishing activities, conservation needs of marine resources and knowledge gaps to be clearly assessed. Such independent reviews are necessary to reduce the exclusive topdown control with poor consideration of the impacts of inaccurate or incomplete information being considered at both local and EU levels when planning for management improvements in the fisheries sector. Both fishermen's skills and nature's ways of adapting to a changing marine environment need to be investigated to assess the resilience of both fishermen and biodiversity in the region. In order to consider such interlinked relationships between SSF and marine species conservation two aspects linking fisheries and endangered native biodiversity are presented here: 1) the Maltese SSF landings of sharks and rays (elasmobranches) species with a case study on how artisanal small-scale fishing of one shark species proves to be sustainable when investigated in detail and 2) Alien (non-native) reef species increasingly discovered in Maltese waters are identified through genetic DNA barcoding and found to be species that may compete or prey on native reef fish, such as groupers and related Serranidae species. The latter already suffering from over exploitation and environmental degradation.

**2. Protecting vulnerable elasmobranch species: targeting marine** 

In the Mediterranean, elasmobranches account for less than 1.5% of the total fish landings in the area [4], therefore their economic importance is much lower than that of teleosts, nonethe-

On a global scale, elasmobranch landing records have shown drastic reduction for several species, with global negative population trends. This has led to a growing list of elasmobranch species within the high risk conservation categories of the IUCN Red List, with over-

At a Mediterranean level, the total number of elasmobranch species inhabiting the region adds up to around 80 [26, 27, 30, 32, 33]. A number of these species have a worse conservation status within the Mediterranean, when compared to their global conservation status since this region is highly populated with evergrowing coastal communities, fishing activities and maritime services, leading to increased pressure on the existing elasmobranch populations, their prey and habitats [27, 28, 30, 31, 34]. In the Mediterranean Sea, higher risk is further exacerbated by limited migration between populations within and outside the region [31, 35].

Despite the increased vulnerability, there are no official records of chondrichthyes that have been totally extirpated from the Mediterranean [27, 28, 31] although there has been a significant decline in their landings both in terms of biomass and numbers, and it is known that some species have disappeared from certain areas [26, 28, 36, 37]. The European landing

less they have an important socio-economic role in Mediterranean fisheries [2, 22, 23].

fishing being the main threat for the declining stocks [24–31].

**biodiversity conservation**

88 Selected Studies in Biodiversity

Traditionally, elasmobranch fisheries in Malta are an integral part of the annual landings, with few local fishermen targeting elasmobranches as primary or secondary target species, while several others capture them as by-catch of various fishing activities [2]. In Malta, these fisheries have always been limited to small-scale fishermen, with most of their operations being carried out within the 25 NM FMZ. However long term direct and indirect pressures have led to drastic reductions and disappearance in the landings of certain species, mostly pelagic sharks such as hammerhead sharks (*Sphyrna* spp.) and porbeagle (*Lamna nasus*) [26], which could have declined not only due to direct exploitation but due to the exploitation of their pelagic prey [26]. Moreover, the life-history of these pelagic species covers wide home ranges and thus the declining stocks are not only influenced by local activities but also by international large-scale fishing activities carried out in neighboring fishing grounds [2]. On the other hand, other elasmobranch species that attract little international interest, are regularly caught, and seem to be more resilient to current anthropogenic pressures. One such example is the small local fishery related to the bluntnose sixgill shark, *Hexanchus griseus*.

Fishing grounds along the South to South-West of Malta are rich in deep submarine canyons with very steep slopes and drop-offs [38]. Such bathymetric features attract a number of species [39–41] and are able to provide the right ecosystems to sustain large top predators including deep-water elasmobranches such as *H. griseus* [38, 42, 43]. The occurrence of these geographical formations within a short distance from major Maltese fishing ports have led few local artisanal fishermen to specifically target *H. griseus* along drop-offs off the Maltese coast both within and outside the FMZ. This fishery is at least a number of decades old [26], with an annual landing record ranging between 1256 (in 1986) and 8529 kg (in 2002), with an average annual record of 4277 kg (±2033 kg) (Malta Fisheries Landing Data 1986–2016) (**Figure 3**). Nonetheless, the apparent lack of interest in the species by other Mediterranean countries does not exclude that *H. griseus* is not being regularly exploited as by-catch, possibly unreported or lumped in other shark categories due to its low economic importance. On a global scale, species-specific landing records for *H. griseus* are scarce [4].

The Maltese landings of *H. griseus* are characterized by seasonal changes, as most of the catches are noted during the first quarter of the year with 49.5% being caught between February and March [44, 45], a time when due to religious traditions several Maltese people tend to prefer consuming fish rather than meat. During this period, the fishing effort targeting deepwater fisheries increases drastically as fishermen having vessels >12 m exploit waters outside the FMZ, with most of the latter employing a small number of fishermen on-board and use demersal bottom long-lines to harvest *H. griseus*. However, these months are characterized by rough seas and thus limits the operations and the fishing effort that these fishermen can dedicate to deep-sea fishing.

**3. Changing marine biodiversity through increasing presence of** 

waters, which have also procured episodes of discomfort for some SSF [47].

Research methods used to study species caught by artisanal fishermen include interview and field surveys, which have allowed the discovery of various concerns, affecting SSF and marine

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Apart from the problems faced by SSF fishermen affected by the limited space available for fishing due to the designations for marine protected areas, aquaculture, tuna penning, swimming, bunkering zones, wrecks, SCUBA diving areas, Freeport and Port activities, there is the increasing concern of marine environmental changes affecting marine life on reefs and coastal waters in particular. Changes due to marine pollution, climate change and anthropogenic introduction of alien species. These changes have also been considered to have affected periodical blooming of gelatinous species in various Mediterranean regions, including Maltese

Alien species presence increasingly observed in the Mediterranean Sea is reported to have been caused by various factors [34, 48]. In turn the increasing number of alien species that become invasive pose serious impacts to fishermen that are faced with strange and unknown species in their catch, some of which are poisonous. Examples of these include the silver-cheeked toadfish (*Lagocephalus sceleratus)* which has expanded its presence in the Mediterranean Sea since its first record from Gökova Bay, Turkey, in 2004 [49]. The lionfish (*Pterois miles*) invasion has also been reported in the Mediterranean Sea [50], after its initial presence was reported in 1991 off Israel [51]. However, as various species entering the Mediterranean become invasive even before detailed analyses on these alien species are undertaken, little is really known about their adaptations and genetics after they spread their distribution into the Mediterranean [52]. For this reason, genetic tools were also used to study alien species

**Species Habitat preference1 Depth range1 Status2 Reference** *Stegastes variabilis* Reef-associated 0–30 m Casual [53] *Lutjanus fulviflamma* Reef-associated 3–35 m Casual [54] *Abudefduf hoefleri* Reef-associated — Established [55] *Abudefduf vaigiensis* Reef-associated 1–15 m Established [56] *Kyphosus vaigiensis* Reef-associated 0–40 m Established [57] *Cephalopholis nigri* Demersal Down to 100 m Casual [58] *Cephalopholis taeniops* Demersal 20–200 m Established [58] *Holocentrus adscensionis* Reef-associated 0–180 m Casual [59] *Acanthurus monroviae* Demersal 5–200 m Established [60]

**Table 1.** A list of the alien fish species recorded in Maltese waters whose identity was confirmed through morphological

**alien species**

1

2

www.fishbase.org.

and genetic analyses.

Status based on criteria by CIESM (www.ciesm.org/atlas/appendix1.html).

biodiversity in Maltese waters.

**Figure 3.** The annual landings (kg) of *Hexanchus griseus* in Malta for the years 1986 till 2016 (Department of Fisheries, National Statistics).

Most of the Maltese fishermen change their fishing strategies depending on the open fishing season, migratory patterns of the species and the local market's needs. Thus as they alter their operations, the fishing effort for demersal deep-water species lowers to target more economically important species such as *Thunnus thynnus*, *Xiphias gladius* and *Coryphaena hippurus*. Nonetheless, some *H. griseus* landings persist throughout the year due to by-catch from trawling activities and by a very few individual fishermen with boats <12 m who fish for demersal deep-water species all year round. The latter use bottom long-lines and alter between different fishing grounds targeting different species, including *H. griseus*.

Although currently there is no direct local or EU legislation limiting landings of *H. griseus*, both Maltese legislation and the EU council regulations [14, 20] identified *H. griseus* as a species that requires monitoring and precautionary management actions to protect the species.

In this scenario, it has to be noted that any protective measures have to consider that in Malta, *H. griseus* is a socio-economically important species to a small number of local small-scale fishermen who have sustainably harvested this resource for decades. Its presence is important to their livelihood especially during the winter months when this shark is caught as an alternative to other commercially important species, while throughout the year it provides a small sustained income to a handful of individual fishermen with small fishing vessels (<12 m). Moreover, given that local fishermen (except trawlers) tend to diversify fishing activities, then *H. griseus* provides another fishing alternative, sustaining a balance between other commercially important species. The current small-scale fishery of this species has benefitted from scientifically based knowledge, which guarantees the survival of the species through an early warning sign of stock depletion, while ensuring the sustainability of its fishery and the livelihood of the fishermen involved [35, 44–46].
