Dolors Vinyoles

Potential impacts of gravel extraction on Spanish populations of river blennies Salaria fluviatilis (Pisces, Blenniidae)

River blennies Salaria fluviatilis have a wide circum-Mediterranean distribution, but they are mostly confined to small, very localised populations. In the Iberian Peninsula, they are endangered due to a variety of causes, including gravel extraction. This study identified the breeding requirements of river blennies at a site where gravel extraction takes place and at three other sites in different drainage basins in Spain. Breeding males chose nest stones that were significantly larger than other stones available in the immediate vicinity. Although clutch area was significantly related to stone size in two of three populations, male size was not. Stone size appeared to be the main correlate of clutch size, and stone sizes were significantly smaller at sites where gravel had been extracted. The potential effects of stone and gravel removal on nesting density and egg productivity were simulated, and it was found that a 75% reduction in stone size, as observed in this study, could result in a 47% decrease in nesting density. Because of the relationship between clutch size and nest stone size, egg production would be reduced even further, to 25% of its initial level. Removal of stones and gravel from the river bed also causes structural alterations which may render the habitat unsuitable for breeding blennies despite the presence of apparently suitable nest stones. Our results may be applicable to the conservation of other substrate-spawning fish.

Outbreaks of Ichthyophthirius multifiliis in Redtail Barbs Barbus haasi in a Mediterranean Stream during Drought

In 2008, inland waterways in Catalonia (northeast Iberian Peninsula, Spain) experienced one of the worst droughts recorded in this region in recent decades. During this period, an epizootic of Ichthyophthirius multifiliis was detected for the first time in a Mediterranean stream, with 21% prevalence in a population of redtail barbs Barbus haasi. Environmental features and the fish population in this stream were compared during 2007-2009. Fish density and the average fish size were reduced significantly after the outbreak of I. multifiliis in this population. During 2008, parasitized fish were significantly larger than nonparasitized fish. In addition, a significant, positive correlation was found between parasite load and fish size. The origin of I. multifiliis is unknown, but an introduced species detected in April 2007 may have carried it. The combination of stress to the redtail barbs due to suboptimal conditions and favorable environmental conditions for parasite multiplication (e.g., suitable water temperature and low water flow) could have enhanced fish susceptibility to the parasite in April 2008. Further studies are needed to establish the incidence of freshwater fish diseases in Mediterranean watersheds, and water management policies should be reviewed to improve the conservation of native fish fauna.

Life-history traits of the stone loach Barbatula barbatula

The life-history tactics of the stone loach Barbatula barbatula were studied in a Mediterranean-type climate stream (Matarranya River) located in the Ebro River basin (north-east Spain). Maximum observed ages were 2+ years in both sexes (1% of individuals), although only 0+ and 1+ year age groups were well represented. It is the lowest longevity reported for this species in its entire distribution. The seasonal growth period started in June and continued until November, but the pattern observed was different to northern populations. Barbatula barbatula in the Matarranya River was a multiple spawner, releasing small batches of oocytes between April and June. The fecundity of females was higher and the size of oocytes smaller in 1984 than in 1985. The relative fecundity (number of ripening and ripe oocytes g(-1) of fish) was lower than in northern European populations. The role of the particular environmental conditions of a Mediterranean stream was discussed in relation to the life-history tactics of B. barbatula.

Wide food availability favours intraspecific trophic segregation in predators: the case of a water snake in a Mediterranean river

In complex aquatic ecosystems, intraspecific competition for food can evolve into dietary differences related to body size, gender, capture ability, and habitat use. The diet of the viperine snake, Natrix maura, an aquatic predator which forages on fish and amphibians, has been studied in parallel with food availability in a small locality of the Matarranya River (NE Spain). Fish abundance values in this Mediterranean river, which hosts one of the highest rates of fish diversity in Europe, were estimated through electrofishing. Natrix maura fed on four of the ten fish species available and captured the only amphibian detected. Three of these fishes were the most abundant species in the river. The fourth fish was the river blenny, a small and rare benthonic species of which the males protect eggs laid under stones at the bottom of the river during reproductive periods. This behaviour makes it easy prey for N. maura. However, the river blenny was caught mostly by small- and medium-sized snakes, while larger individuals, particularly females, fed on larger and more mobile prey that were more abundant and energetically more profitable. Similar diet differences according to size and gender have been described in other water snakes. We discuss whether this coincidence may be related to the great tropic availability in aquatic environments for fish-eating snakes.

Long-Term Macroevaluation of Environmental Enrichment in Three Brown Bears (Ursus arctos) at Barcelona Zoo.

The evaluation of enrichment programs is important to determine their effect on nonhuman animal welfare. The daily activity pattern and use of space of 3 brown bears (Ursus arctos) were used for long-term macroevaluation of enrichment to compare the baseline and enrichment phases. Focal sampling methods were used for data collection, and instantaneous scans were made at 2-min intervals during 15 sessions of 1 hr for each animal during the 2 study periods. The enrichment devices were categorized as feeding, occupational, and sensorial. The long-term macroevaluation in 3 bears showed statistically significant differences in some types of activity but not in others. There were also statistically significant differences for the use of space in 4 of the 8 zones in which the enclosures were divided. A more homogenous pattern in the use of space was only observed during the enrichment phase in the old female. The 3 brown bears followed different patterns concerning the enrichment program.

Improving the Welfare of a Zoo-Housed Male Drill (Mandrillus leucophaeus poensis) Aggressive Toward Visitors

Improving the welfare of nonhuman animals in captivity and maintaining behavioral competence for future conservation purposes is of the highest priority for zoos. The behavior of an aggressive male drill (Mandrillus leucophaeus poensis) was assessed in Barcelona Zoo. The 2-year study presented in this article examined the effects of introducing changes in the exhibit of the drill to improve his welfare by analyzing scan behaviors. First, a partial visual barrier was applied and proved to be insufficient to decrease the long-term stress indicators assessed. Next, a feeding enrichment program was implemented. The results supported the hypothesis that feeding and explorative activities would increase, whereas apathetic and stereotypic behaviors would decrease. However, visitor-directed aggression did not vary, indicating that more profound structural modifications were needed to reduce the negative impact of the agonistic interactions between the drill and the public. The study emphasized the usefulness of environmental enrichment evaluations in assessing captive animal welfare.