Recolonisation and recruitment of fishes to intertidal rockpools at Wellington, New Zealand

Synopsis A study of recolonisation of rockpools by intertidal fishes on the Wellington south coast, New Zealand, found the assemblage to be resilient and seasonally stable. A total of 26 species from nine families were recorded, dominated by the Tripterygiidae (triplefins) and Gobiesocidae (clingfishes). A pattern of alternating species dominance occurred, with the triplefinsBellapiscis medius andForsterygion lapillum being numerically dominant in summer, but becoming less common in winter and replaced as dominants by the clingfishesTrachelochismus pinnulatus andGastroscyphus hectoris. Juvenile recruits of eleven species occurred in the samples from spring to early summer, however only the aforementioned four species recruit to the intertidal zone in large numbers. The speed of rockpool recolonisation by fishes after extractive sampling is seasonally dependent, being quicker in the summer than winter. In general, recolonisation takes at least one month, but probably fewer than three. While stochastic factors influence assemblage composition in the short term, overall regulation of the fish assemblage of rockpools appears to be primarily deterministic, resulting in an essentially predictable taxonomic structure.     

Two new and one known species of <Emphasis Type="Italic">Tergestia</Emphasis> Stossich, 1899 (Trematoda: Fellodistomidae) with novel molecular characterisation for the genus

Combined morphological and molecular analyses are employed to characterise three species of Tergestia Stossich, 1899 (Digenea: Fellodistomidae) from fishes of Moreton Bay, Queensland, Australia. Tergestia clonacantha Manter, 1963 is reported here for the first time from the halfbeak (Beloniformes: Hemiramphidae) species Arrhamphus sclerolepis krefftii (Steindachner), Hyporhamphus australis (Steindachner), H. quoyi (Valenciennes) and H. regularis ardelio (Whitley). Two new species, both infecting trevally (Perciformes: Carangidae) species, are described: T. maryae n. sp. from Alepes apercna Grant and T. henryi n. sp. from Pantolabus radiatus (MacLeay). Complete ITS2 and partial 28S ribosomal DNA data were generated for each of the new taxa. The three species differ from each other by 47–58 base pairs (bp) in the ITS2 rDNA region. Phylogenetic analysis of 28S rDNA supports Tergestia as a reliable generic concept, with our analyses showing that some species of the genus form a well-supported clade to the exclusion of all other fellodistomids for which sequence data are available.     

<Emphasis Type="Italic">Capillaria appendigera</Emphasis> n. sp. (Nematoda: Capillariidae) from the goldbanded jobfish <Emphasis Type="Italic">Pristipomoides multidens</Emphasis> (Day) (Lutjanidae) and new records of other intestinal capillariids from marine perciform fishes off Australia

Based on light and scanning electron microscopical studies, a new nematode parasite, Capillaria appendigera n. sp. (Capillariidae), is described from the intestine of the goldbanded jobfish Pristipomoides multidens (Day) (Perciformes, Lutjanidae) from the Arafura Sea West, off the northern coast of Australia. The new species, belonging to the subgenus Procapillaria Moravec, 1987, differs from other congeneric species from fishes mainly in the length (0.92–1.13 mm), shape and structure of the spicule, obtuse spines on the spicule sheath and the structure of eggs. It is characterised, in the male, by the presence of two well-developed dorsolateral caudal lobes, a pair of lateral papillae, a heavily sclerotised spicule with many rough transverse grooves covering almost the entice spicule surface (except for spicule ends), a spinose spicule sheath, and in the female, by a subterminal anus, mostly the presence of a large vulval appendage and by eggs (size 54–69 × 27–33 µm) encapsulated by a conspicuous light-coloured superficial layer. Capillaria appendigera n. sp. is the 12th nominal species of capillariids recorded from fishes in Australian waters and the second known capillariid species parasitising fishes of the perciform family Lutjanidae. In addition, four unidentifiable, morphologically different types of capillariid females, probably representing undescribed species, were recorded from the intestines of marine fishes off the northern coast of Australia: Capillariidae gen. sp. 1 and Capillariidae gen. sp. 2 from Lutjanus johnii (Bloch) and L. malabaricus (Bloch & Schneider), respectively (both Lutjanidae), Capillariidae gen. sp. 3 from Protonibea diacanthus (Lacépède) (Sciaenidae) and Capillariidae gen. sp. 4 from Rachycentron canadum (Linnaeus) (Rachycentridae).     

Transport pathways shape the biogeography of alien freshwater fishes in Australia

Aim

Changing preferences regarding which species humans have transported to new regions can have major consequences for the potential distribution of alien taxa, but the mechanisms shaping these patterns are poorly understood. We assessed the extent to which changes in human preferences for transporting and introducing alien freshwater fishes have altered their biogeography.

Location

Australia.

Methods

We compiled an up‐to‐date database of alien freshwater fishes established in drainages in Australia before and after the number of established alien fish species doubled (pre‐1970 and post‐1970, respectively). Using metacommunity models, we analysed the influence of species traits and drainage features on the distribution of alien fishes that established pre‐ and post‐1970.

Results

Alien fishes in Australia were introduced via four main transport pathways: acclimatization, aquaculture, biocontrol and ornamental trade. The relative importance of each pathway changed substantially between the two periods, accompanied by changes in the distribution of alien fishes and the variables predicting their distribution. Pre‐1970, most species (64%) were introduced by acclimatization societies for purposes such as angling and biocontrol, and these fish have established in inland drainages more heavily impacted by human activities. In contrast, most of the post‐1970 introductions (69%) were ornamental fishes, with most species established in small, north‐eastern, tropical and subtropical coastal drainages.

Main conclusions

Substantial changes in introduction preferences and transport pathways over time have altered both the patterns and underlying processes shaping the biogeography of alien fishes in Australia. Our findings highlight the need for caution when using historical data to infer potential future distributions of alien species. The continuing spread of alien species means traditional biogeographical units may no longer be identifiable in the foreseeable future.

     

Rhenanoperca minuta nov. gen., nov. sp., ein neuer Percoide (Pisces,Perciformes) aus der Messel-Formation (Mittel-Eozän,Unteres Geiseltalium)

A new genus and species of percoid fishes (Pisces, Perciformes) from the Middle-Eocene Messel-Formation is introduced and delimitated from other palaeogene percoids. A preliminary diagnosis is proposed. As the relationships of this new taxon still remain somewhat imprecise, it is provisionally classified as “Percoidei incertae familiae”.     

New Zealand triplefin fishes (family Tripterygiidae): contrasting population structure and mtDNA diversity within a marine species flock

Triplefin fishes (Family Tripterygiidae) dominate the New Zealand temperate coastal fish fauna in diversity (26 endemic species, 14 genera). Most species appear to have evolved as a local radiation and mostly occupy sympatric distributions throughout New Zealand. To investigate the forces driving current gene‐flow patterns and past evolutionary histories, we searched for common patterns of population genetic subdivision within eight species sampled throughout their distributions [mitchochondrial DNA (mtDNA) control region, n = 1086]. We hypothesised that common phylogeographical and population differentiation patterns would reveal past or ongoing physical processes, with differences reflecting stochastic or species‐specific processes. Striking differences between species were apparent, with strong phylogeographical structure detected in Grahamina capito and the estuarine species G. nigripenne. G. capito fell into three distinct geographically restricted lineages. G. nigripenne largely separated into northern and southern lineages (Φ_ST 0.834). Strong population structuring and isolation by distance was evident in Bellapiscis medius, B. lesleyae and Forsterygion lapillum (Φ_ST 0.686, 0.436 and 0.115, respectively). High gene flow was apparent in G. gymnota and Ruanoho whero, and F. varium. However, for the latter species, isolation was apparent with samples collected from the offshore Three Kings Islands. Overall, a strong relationship was found between habitat depth and population structure among species, and species inhabiting shallower water habitats showed lower genetic diversity with higher levels of population subdivision. High‐latitude populations generally showed low haplotype and nucleotide diversity. These data suggest that processes resulting from intraspecific differences in habitat preference, climatic histories and/or larval ecologies have subdivided populations of shallow water triplefin species.     

<Emphasis Type="Italic">Lobocapillaria austropacifica</Emphasis> n. g., n. sp. (Nematoda: Capillariidae) from the obtuse barracuda <Emphasis Type="Italic">Sphyraena obtusata</Emphasis> Cuvier (Sphyraenidae,Perciformes) off eastern Australia

Based on light and scanning electron microscopical studies, a new nematode parasite, Lobocapillaria austropacifica n. sp. (Capillariidae), is described from the gall-bladder of the marine fish (obtuse barracuda) Sphyraena obtusata Cuvier (Perciformes: Sphyraenidae) from off the eastern Pacific coast of Australia, for which a new genus Lobocapillaria n. g. is established. This new genus is mainly characterised by a single row of stichocytes, the presence of two large, conspicuously elongated lateral caudal lobes and a pair of subventral papillae at their base in males, a flat spicule distended laterally towards its proximal end and provided with superficial rough transverse grooves, a spicular canal and a very long, aspinose spicular sheath with a conspicuous expansion near its proximal end when evaginated. Capillaria sphyraeni Parukhin, 1971 is transferred to Lobocapillaria as L. sphyreni (Parukhin, 1971) n. comb. A key to capillariid genera containing species parasitic in fishes is provided.     

<Emphasis Type="Italic">Barracudia australiensis</Emphasis> n. g., n. sp. (Nematoda: Philometridae) from the obtuse barracuda <Emphasis Type="Italic">Sphyraena obtusata</Emphasis> Cuvier (Perciformes: Sphyraenidae) off eastern Australia

Based on light and scanning electron microscopical studies, a new nematode parasite, Barracudia australiensis n. sp. (Philometridae), is described from the gall-bladder of the marine fish (obtuse barracuda) Sphyraena obtusata Cuvier (Sphyraenidae, Perciformes) from off the eastern Pacific coast of Australia, for which a new genus Barracudia n. g. is established. This new genus is mainly characterised by features found in the male: sickle-shaped, ventrally curved spicules, a gubernacum with a broad, dorsally bent distal portion and a markedly dorsoventrally elongated cloacal aperture. Based on these features, Barracudia spp. conspicuously differ from representatives of all other philometrid genera with known males. Philometra philippinensis Quiazon & Yoshinaga, 2013 is transferred to Barracudia as B. philippinensis (Quiazon & Yoshinaga, 2013) n. comb. Barracudia australiensis is the third nominal species of philometrids described from the Sphyraenidae and the 19th species of the Philometridae recorded from fishes in Australian waters.     

Functional morphology of the caudal region of certain clupeiform and perciform fishes with reference to the taxonomy

The caudal anatomy (caudal skeleton, musculature, vascularization, innervation, and urohypophysis) and swimming behavior of three clupeiform and three perciform fishes: Elops hawaiensis (Cupeiformes: Elopidae), Oncorhynchus nerka (Cupeiformes: Salmonidae), Chanos chanos (Clupeiformes: Chanidae), Kuhlia sandvicensis (Perciformes: Kuhlidae), Apogon menesemus (Perciformes: Apogonidae), and Gnathanodon speciousus (Perciformes: Carangidae), were studdied. The taxonomic significance of caudal structures was determined and evaluated by detailed examination of differences in caudal anatomy. An interpretation of functional significance of these differences was attempted by relating them to observed differences in swimming behavior. The swimming behavior was studied by the observation of swimming activities of fish while resting or cruising and while feeding in the aquarium, and by an analysis of each frame of an 8 mm movie film of swimming activities. There are certain consistent and basic differences between all three species of the order Clupeiformes and all three species of the order Perciformes in respect to caudal structures. Although certain caudal structures show overlapping in number and/or complexity of arrangement, they seem to indicate more complex structural organization in Clupeiformes than Perciformes. The differences confirm the conclusion of others that the order Clupeiformes is more “primitive” than the order Perciformes. With respect to caudal structures of the three clupeiform species studied, E. hawaiensis is the most “primitive” and, of the three perciform species studied, K. sandvicensis is the most “primitive.” Caudal structural variations from one species to another are related to the mode of adaptation to swimming as well as to the evolutionary status of the species.     

The behavioural thermal preference of the common triplefin (Forsterygion lapillum) tracks aerobic scope optima at the upper thermal limit of its distribution

Ocean temperatures are rising and fish are redistributing themselves poleward and into deeper waters to retain a favourable thermal environment (11 and 30). To investigate whether biogeographical shifts might occur through behavioural redistribution into optimal environments, we examined whether a common triplefin species (Forsterygion lapillum) would behaviourally select (i.e. track) a temperature that matches its physiological optimum under laboratory conditions. F. lapillum were acclimated to 15, 18 or 21 °C for at least 4 weeks, after which various rates of oxygen consumption (MO₂) were measured using automated respirometry and their behavioural thermal preferenda assessed using an electronic shuttle choice tank. Aerobic metabolic scope (resolved as the difference between maximal and maintenance MO₂) did not differ across all thermal treatments (i.e. specimens acclimated to 15, 18 or 21 °C) revealing that F. lapillum is a eurythermal species with a range of optimal physiological performance that closely matches the environmental conditions they are exposed to. A comparably wide range of behavioural preference would perhaps be expected but all three acclimation groups showed a surprisingly narrow behavioural preference range of 20–21 °C. The results therefore suggest that, irrespective of acclimation, eurythermal species may have a tendency to select optimal temperatures at the upper limit of their thermal distribution range. The results are discussed in the context of the ecology and the expected response of F. lapillum to future thermal change.     

Diplobulbus brayi n. sp. (Digenea: Opecoelidae) from Odax acroptilus (Perciformes: Odacidae) off Western Australia

Diplobulbus brayi n. sp. is described from the small intestine of Odax acroptilus (Perciformes: Odacidae) from Point Peron in southern Western Australia. One of the five previously described species of Diplobulbus, D. vitellosus Bilqees, 1972 from Tetraodon lunaris (now Lagocephalus lunaris), is synonymised with Alloheterolebes indicus (Gupta, 1968) Hafeezullah, 1971, which is known from the same host in the Indian Ocean. D. brayi n. sp. can be distinguished from the remaining four species of Diplobulbus by the distinct interruption of the vitelline follicles at the ventral sucker, its more elongate form and its long post-testicular space. Diplobulbus is so far restricted to the Indo-Pacific region and appears to be stenoxenic to labroid fishes. This is the first record of a trematode from an odacid fish.     

First report of gastrocotylinean post-oncomiracidia (Platyhelminthes: Monogenoidea: Heteronchoinea) on gills of flyingfish (Exocoetidae), snapper (Lutjanidae), dolphinfish (Coryphaenidae), and amberjack (Carangidae) from the Gulf of Mexico: decoy hosts and the dilution effect

Larvae, identified as post-oncomiracidia of the suborder Gastrocotylinea (Monogenoidea), were collected from formalin-fixed gills excised from six species of marine fishes captured from the Gulf of Mexico off Mississippi and Florida: common dolphinfish, Coryphaena hippurus and pompano dolphinfish, Coryphaena equiselis (both Perciformes, Coryphaenidae); gray snapper, Lutjanus griseus (Perciformes, Lutjanidae); greater amberjack, Seriola dumerili (Perciformes, Carangidae); and Atlantic flyingfish, Cheilopogon melanurus and sailfin flyingfish, Parexocoetus hillianus (both Beloniformes and Exocoetidae). Based on a combination of diagnostic morphological features, the specimens were divided into two basic forms, each of which was further subdivided into two morphotypes. No gastrocotylinean post-oncomiracidium had been reported previously from these hosts. Of the six host species, only C. hippurus serves as a host (unconfirmed) for the adult of a gastrocotylinean species, suggesting that the recorded fishes from the Gulf of Mexico comprise dead-end hosts acting as decoys for the oncomiracidia. These comparatively non-susceptible “decoy hosts” apparently dilute the susceptible fish-host population and by intercepting infective larvae (oncomiracidia) decrease the abundance of parasites on their typical hosts.     

胶州湾海域鱼类群落种类组成及多样性

为了解胶州湾海域鱼类群落结构特征,根据2016—2017年间对胶州湾海域进行的4个航次底拖网调查数据,采用相对重要性指数、生态多样性指数和典范对应分析(canonical correspondence analysis,CCA)、非线性多维标度排序(non-metric multidimensional scaling,NMDS)等方法分析了胶州湾海域鱼类群落的种类组成和多样性特征。结果表明:调查共采集到鱼类46种,隶属2纲10目30科41属,以硬骨鱼纲鱼类为主(45种,97.83%)。其中,鲈形目(Perciformes)最多(22种,47.83%),其次是鲉形目(Scorpaeniformes),占15.22%。种类数季节变化明显,以夏季最高,23种;秋季最低,16种。优势种组成以赤鼻棱鳀(Thryssa kammalensis)、褐菖鲉(Sebastiscus marmoratus)、褐牙鲆(Paralichthys olivaceus)、大泷六线鱼(Hexagrammos otakii)、许氏平鮋(Sebastes schlegeli)和矛尾鰕虎鱼(Chaeturichthys stigmatias)等鱼类为主。多样性分析显示,鱼类物种多样性存在明显的季节差异。多样性指数(H′)季节变化范围为1.668—2.453,以夏季最高,春季最低;均匀度指数(J′)季节变化范围为0.577—0.808,以秋季最高,春季最低;丰富度指数(D′)季节变化范围为2.431—3.123,以冬季最高,秋季最低。典范对应分析表明,水温、盐度、水深和pH是影响胶州湾海域鱼类群落物种组成的主要环境因子,且水温和pH是影响鱼类群落结构及多样性时空变化的主要因子。与历史调查资料相比,由于人类活动对胶州湾生态系统的干扰,鱼类群落结构发生了较大变化,优势种组成更替明显,多样性水平降低,鱼类群落结构趋向简单化。     

Experimental taxonomy of Australian mites in theMacrocheles glaber group (Acarina: Macrochelidae)

Mites which are abundant in southeastern Australia, and which have been tentatively identified asMacrocheles glaber on the basis of the appearance of the adult female, are shown to be a composite of two species when morphological features of the adult males are considered. These species are tentatively identified on morphological grounds asM. glaber (Müller) andM. perglaber Filipponi and Pegazzano. Populations of these two species imported from France are shown to be capable of interbreeding with their Australian counterparts, thus supporting the identification of the two species found in Australia.M. peregrinus Krantz, introduced into Australia from southern Africa, is shown to be incapable of interbreeding withM. perglaber. The demonstration thatM. glaber andM. perglaber both already exist in the field in Australia indicates that their deliberate introduction now would not contribute to the biological control of dung-breeding flies.     

Ascarophisnema hoiae n. sp. (Nematoda: Cystidicolidae), from the stomach of the trumpeter whiting,Sillago maculata Quoy & Gaimard (Perciformes: Sillaginidae) from Moreton Bay,Queensland, Australia

Ascarophisnema hoiae n. sp. (Nematoda: Cystidicolidae) is described from the stomach of the trumpeter whiting, Sillago maculata Quoy & Gaimard (Perciformes: Sillaginidae) from Moreton Bay, Queensland, Australia. It differs morphologically from the only other valid congener, A. tridentatum Moravec & Justine, 2010 in the shape of the sub-labium and in the lengths of the spicules and the morphology of their distal tips (bifid). It represents the first record of this genus from Australia and appears to be highly oioxenous, having been found only in this host species among 133 other species of fish examined at the same locality.

     

Two new species of <Emphasis Type="Italic">Sagum</Emphasis> Wilson, 1913 (Copepoda: Siphonostomatoida: Lernanthropidae) parasitic on reef fishes off the Ryukyu Islands

Two new species of parasitic copepods, Sagum gurukun n. sp. and S. bitaro n. sp. (Siphonostomatoida: Lernanthropidae), are described based on specimens collected from the gill filaments of the double-lined fusilier Pterocaesio digramma (Bleeker) (Actinopterygii: Perciformes: Caesionidae) and the five-lined snapper Lutjanus quinquelineatus (Bloch) (Actinopterygii: Perciformes: Lutjanidae), respectively, caught off Iriomote-jima Island, the Ryukyu Islands, East China Sea, Japan. The findings bring the number of species of Sagum to 14. The two new species are similar in the morphology of the head and the legs 3 and 4 to the three congeners, S. folium Ho, Liu & Liu, 2011, S. paracaesionis Izawa, 2014 and S. vietnamiensis Kazachenko, Kovaleva, Nguyen & Ngo, 2017. Sagum gurukun n. sp. is differentiated from the three congeners by the proportions of the caudal rami, the absence of leg 5, and the shape of the legs 1 and 2. Sagum bitaro n. sp. differs from the three congeners and S. gurukun n. sp. by the presence of the conical leg 5 armed with an apical seta. A key to the species of the genus Sagum, based on the available information on female morphology in previous publications and the present study, is provided. To date, a total of 19 species of lernanthropid copepods considered valid are known in Japanese waters.     

Feeding habits and seasonal trophic guilds structuring fish community in the bay mouth region of a tropical estuarine habitat

Understanding trophic relationships of fish in estuarine ecosystem is an important element for sustainable resource management. This study examined the feeding habits of 29 dominant fish species, characterized the trophic guilds, assessed the impact of season and clarified the role of diets in structuring the fish community in the mouth region of Pattani Bay, Thailand. Samples of 5792 fishes collected monthly by gillnets from March 2019 to February 2020 were used for stomach content analyses. It was found that the number of food types and fullness index differed between fish taxa (P < 0.001). Most fishes were specialist feeders feeding on specific food components and were categorized into five trophic guilds: piscivore, shrimp-fish feeder, polychaete feeder, zooplanktivore and planktivore. Six species were piscivorous, considered as apex predators, that fed almost entirely on fishes. High diet overlaps among some species (>0.6) were recorded. Not much variation in seasonal guilds was observed: four guilds in the dry season, three in the moderate rainy season and four in the rainy season. Some species remained in the same guild the whole year round, but some fishes changed seasonally. Two fish communities from different regions of the bay were segregated based on feeding habits. The inner bay community comprised mainly copepod and plankton feeders, but there were more piscivores in the deeper bay mouth area. Results from this study help us to understand the feeding habits and trophic guilds of dominant fish species at the mouth of this tropical estuarine bay.     

Dichelyne (Cucullanellus) bodiani n. sp. and Cucullanus hansoni Olsen, 1952 (Nematoda: Cucullanidae) from fishes off New Caledonia

Two species of cucullanid nematodes collected from the intestine of marine fishes off New Caledonia were studied with the use of light and scanning electron microscopy (SEM): Dichelyne (Cucullanellus) bodiani n. sp. from Bodianus perditio (Quoy & Gaimard) (Perciformes: Labridae), characterised mainly by the small size of the body (males and gravid females 2.26–3.13 mm and 2.46–3.32 mm long, respectively), the presence of very long spicules (1.53–1.66 mm in length), the remarkably large seminal vesicle and the arrangement of caudal papillae, is the second known species of Dichelyne Jägerskiöld, 1902 parasitising fishes of the Labridae and the second nominal species of this genus recorded from fishes in New Caledonian waters. Cucullanus hansoni Olsen, 1952, originally described from Hawaii, is now, after 67 years, again reported from its type-host, Sufflamen fraenatum (Latreille) (Tetraodontiformes: Balistidae), from off New Caledonia. The SEM examination of C. hansoni, used in this species for the first time, revealed some new morphological details, such as the presence of a median precloacal cuticular elevation or the shape of deirids and distal tips of spicules, as well as the exact location of caudal papillae and phasmids in the male. This is the seventh species of Cucullanus Müller, 1777 recorded from fishes off New Caledonia.