Residency and behavioural rhythmicity of ballan wrasse (Labrus bergylta) and rays (Raja spp.) captured in Portelet Bay, Jersey: implications for Marine Protected Area design

Abstract

We monitored the long-term residency of reef-associated ballan wrasse and sand-dwelling rays captured at the site of a potential future Marine Protected Area (MPA: Portelet Bay, Jersey) by implanting them with small transmitters and deploying underwater receivers inside the bay. Individual fish were detected at Portelet Bay for up to 618 days, but there were species-specific differences in residency and detection patterns. Ballan wrasse were year-round residents at the study site where they exhibited distinct, rhythmic, diel, tidal and seasonal patterns of behaviour, whereas rays were occasional visitors to Portelet Bay with no discernible pattern to their visits. Results indicate relatively small MPAs (<0.5 km2) that with suitable habitat could provide effective, long-term protection for ballan wrasse, but would likely be of little conservation benefit for rays. Our findings emphasize the importance of quantifying fish movements when planning MPAs which intend to protect multi-species assemblages of coastal fishes.

Sustainable production and use of cleaner fish for the biological control of sea lice: recent advances and current challenges

“…Ballan wrasse and lumpish are diurnal species; they are active during the day, when they are likely to exhibit delousing behaviour, and rest at night. [41][42][43] Lumpish tend to swim at shallower depths than ballan wrasse, which adjusted their swimming depth according to the time of day in commercial net-pen trials 43 (table 2). The species' diferences in temperature preferences and behaviour suggest that a combined wrasse/lumpish deployment strategy may prove to be more efective than a single-species approach.…”

“…Water temperature is an important consideration for both ballan wrasse and lumpfish as it dictates their deployment windows. The ballan wrasse is a temperate species and tends to have slower swimming and foraging activity at temperatures below 10°C 40 , and below 6°C they enter into a state of torpor 41 (table 2). In contrast, lumpfish continue to feed at 4°C, 27 but industry reports suggest that they prefer lower temperatures and are more prone to disease at higher temperatures (>10°C).…”

Gender distribution, sexual size dimorphism and morphometric sexing in ballan wrasse Labrus bergylta

“…Labrus bergylta is a monandric protogynous hermaphrodite with a haremic mating system where males assert territorial dominance over an area with several females (Sjolander et al , ; Darwall et al , ). This reproductive strategy is associated with strong site fidelity (Morel et al , ) and a skewed sex ratio in wild populations ( c. 10% male; Quignard, ; Dipper et al , ). Sexual inversion was previously observed between the ages of 5 and 14 years (Dipper et al , ) with age at 50% sex change evaluated at 7·4–11·8 years (Villegas‐Ríos et al , 2013 a ).…”

Pre-deployment acclimatisation of farmed ballan wrasse (Labrus bergylta) to sea-cage conditions promotes behaviour analogous to wild conspecifics when used as cleaner fish in Atlantic salmon (Salmo salar) farms

“…Hides are considered essential for wrasse maintenance in salmon sea cages (Treasurer, 2013), and although they were used very little by the fish in this study, they do seem to have a role in providing suitable structures to attract the wrasse. As this study was conducted during the summer, it may be that hides are used more at low winter temperatures when ballan wrasse are known to enter a state of torpor (Morel et al, 2013), although hide use was also relatively low in a similar study conducted at lower temperatures in March-May (Leclercq et al, 2018). Wild wrasse spent very little time in the centre of the cage where the majority of the salmon biomass can be found, and core areas of the wild wrasses' ranges (KUD50) nearly always incorporated hide corners (with some in empty corners).…”