Feeding of a larval clinid fish in a microtidal estuary from southern Chile

2017

Sci. Mar.

The majority of rocky reef fishes have complex life cycles, involving transition from a pelagic to a benthic environment. This means that as they grow, their morphology, behaviour and feeding habits must change. Therefore, shape changes occurring during early development of these fishes will be related to diet changes. The clingfish Sicyases sanguineus was selected for this study, because it displays a noticeable variation in shape from pelagic larvae to juvenile stage, and it is expected that diet composition will change as well. The pattern of shape changes was studied using geometric morphometrics. A set of 9 landmarks were digitized in 159 larval and juvenile fish and the same specimens were used for gut content analysis. Allometric growth was most prominent early in the ontogeny, from 4 to 12 mm. Morphology changed from a thin and hydrodynamic shape to a more robust and deeper body prior to settlement. The diet of the clingfish during larval stages showed preferences for a variety of copepod stages. As individual grows the ingested prey volume increases, but not the number and width of prey. A partial least square analysis showed low covariance between shape changes and diet composition changes in prey number and volume, suggesting that the two processes were temporally decoupled. The biggest shape changes, a lengthening of the visceral cavity and a flattening of the head, occurred up to 12 mm standard length, while the largest feeding differentiation, shifting from copepods to microalgae, occurred after 16 mm. Results suggest that shape changes precede trophic changes in this clingfish species during the transition from a pelagic to a benthic habitat.

Section: Discussionsupporting

confidence: 71%

Section: Discussionmentioning

confidence: 77%

Feeding variations and shape changes of a temperate reef clingfish during its early ontogeny

Bernal-Durán

2017

Sci. Mar.

“…Labrisomid blenny Auchenionchus variolosus mainly ate copepods and its early stages –mostly copepod nauplii, as with the majority of other marine fish larvae from different habitats such as the tropics (Sampey et al., ), fjords (Landaeta et al., ), open ocean (Sassa and Tsukamoto, ) and estuaries (Ochoa‐Muñoz et al., ). However, it is relevant to note that a significant decrease in the relative importance of nauplii occurred from the austral spring 2012 (~90%) to spring 2013 (~50–73%), changing to copepodites.…”

Section: Discussionmentioning

confidence: 99%

Diet of labrisomid blennyAuchenionchus variolosus(Valenciennes, 1836) (Labrisomidae) during its larval development off central Chile (2012-2013)

Vera‐Duarte

2015

J. Appl. Ichthyol.

Summary The diet, feeding success (prey number and total volume per gut, and maximum prey width) and trophic niche width of the labrisomid blenny Auchenionchus variolosus (Valenciennes, 1836) was studied during its larval development (3.93–17.26 mm standard length). Individuals were collected in October 2012 and October 2013 in nearshore waters (<500 m offshore) from Bahía Valparaíso, central Chile with Bongo nets. When compared to the same length range, larval A. variolosus collected during 2013 showed larger upper jaw‐at‐sizes than those from 2012. This coincided with a reduction in relative importance (%IRI) of the main prey item, copepod nauplii, from ~90 to ~73%. Feeding incidence (FI) was high throughout larval development, varying from 97.3 to 100%, being similar throughout the larval development. Prey items per gut (PIPG) ranged from 0 to 35 prey, showing no differences among years. Total volume per gut (TVPG) was positively correlated with larval length, and at given larval size, TVPG ingested by larval A. variolosus was larger during 2013 (0.0607 mm3) than during 2012 (0.0301 mm3). Prey width range was 47.47–700.94 μm and was positively correlated with standard length (SL). Niche breadth was independent of larval size and did not change during larval development in 2012 or 2013. The study helps to understand the trophic interactions occurring in nearshore waters off rocky reef environments from mid‐latitudes of the Southeast Pacific coasts.

“…Once these parasites enter their intermediate hosts, they cannot detach, and transmission to the next host occurs via a passive route, through predation. Fish larvae feed on planktonic organisms such as the calanoid copepods, nauplii, copepodids and eggs of various crustaceans, ostracods, and the larvae of bivalves and polychaetes (Balbontín et al 1997, Ochoa-Muñoz et al 2013. All of these organisms exhibit small sizes and short life-spans, which reduces their likelihood of becoming parasitised (González 1998).…”

Section: Species Richness Of Parasites On Fish Larvaementioning

confidence: 99%

Parasite richness in fish larvae from the nearshore waters of central and northern Chile

Muñoz

Palacios-Fuentes

et al. 2015

Folia Parasitologica

In the present study, we determine the presence of parasites in fish larvae collected from nearshore waters along the northern and central coast of Chile. The parasites were identified to the lowest possible taxonomic level based on morphological and molecular analyses. The fish sample was composed of 5 574 fish larvae. Of these, 3% harboured only larval ectoparasitic copepods whereas no endoparasites were found in the 1 141 fish evaluated for this group of parasites. The parasitic copepods collected were initially classified as 'morphotypes' according to differences in morphological characteristics. They were then analysed using molecular techniques based on the 28S and COI genes. Seven morphotypes of parasitic copepods (mostly at chalimus stages) were recognised: two of the morphotypes belonged to Pennellidae Burmeister, 1835, three to Caligidae Burmeister, 1835 and two were not identified. Only five morphotypes of copepods were analysed using molecular sequences, which confirmed the existence of six species: two pennellids of the genus Trifur Wilson, 1917 and two caligids of the genus Caligus Müller, 1785, plus two additional species that were morphologically different from these taxa. The pennellids were present in several fish species, being generally more prevalent than the caligids, in both the central and northern localities of Chile. Multispecies infections in larval fish were infrequent (< 1%). We conclude that fish larvae were rich in parasites, considering that these hosts exhibited small body sizes and were very young. We suggest that fish larvae could play a role, as intermediate hosts, in the life cycle of the parasitic copepods found.