Fin healing and regeneration in sturgeon

Abstract

Pectoral fin healing in fin spines and rays were examined in juvenile Atlantic sturgeon Acipenser oxyrinchus oxyrinchus following three different sampling techniques (n = 8-9 fish per treatment): entire leading fin spine removed, a 1-2 cm portion removed near the point of articulation, or a 1-2 cm portion removed from a secondary fin ray. Also, to determine whether antibiotic treatment influences healing, an additional group of fish (n = 8) was not given an injection of an oxytetracycline (OTC)-based antibiotic following removal of the entire leading fin spine. Following fin sampling, fish from different treatments were mixed equally between three large (4,000 I) recirculating systems and fin-ray healing and mortality were monitored over a 12 month period. To assess healing, blood samples were collected at 4 months to measure immune system responses, radiographs were taken at 4, 8 and 12 months to assess the degree of calcification in regions of damaged fins and fins were analyzed histologically at 12 months. Fish grew from a mean weight of 1.8 to 3.2 kg during the experiment and survival was near 100% in all treatments, with only one fish dying of unknown causes. Leukocyte counts, an indication of health status and survival were similar among treatments and in groups with or without antibiotic injection. Radiographs revealed mineralization took longer in fish with the entire leading fin spine removed and was the slowest near the point of articulation, presumably due to the greater structural support for the pectoral fin at this location. Histological sampling indicated spines and rays had similar healing patterns. Following injury, an orderly matrix of collagen bundles and many evenly spaced scleroblasts were present, transitioning to Sharpey fibres, with concentric layers forming lamellar bone. Healing and mineralization were characterized as periosteal osteogenesis and included embedded osteocytes surrounded by an osteoid seam. Chondroid formation was apparent in a few fractures not associated with treatments. The duration of time for external wound healing and internal mineralization of spines and rays depended on the fin treatment, with the slowest healing observed in fish with the most tissue removed, the entire leading fin spine.

Identification of Hatchery‐Reared Lake Sturgeon Using Natural Elemental Signatures and Elemental Marking of Fin Rays

“…In addition, Allen et al. (2018a) confirmed that the complete regeneration of the pectoral fin ray in juvenile Atlantic Sturgeon was achieved after 12 months of healing. With specific reference to Lake Sturgeon (the focus of our study), a recent mark–recapture study from the Winnipeg River (wherein all juvenile Lake Sturgeon captured had fin rays removed for aging) produced annual survival estimates of 0.99 (McDougall et al.…”

No Correlation between Endo- and Exoskeletal Regenerative Capacities in Teleost Species

“…The dermal fin folds are useful during swimming, but due to their fine structure, they can get easily injured, therefore, the capacity to regenerate them has clear adaptive value. Exoskeletal regeneration has been described in many Actinopterygian species, (e.g., sturgeon (Acipenser oxyrinchus) [35], short-lived killifish (Nothobranchius furzeri) [36], sailfin molly (Poecilia latipinna) [37], mexican cavefish (Astyanax mexicanus) [38], medaka (Oryzias latipes) [39], loach (Paramisgurnus dabryanu) [40] and several others [41]), suggesting that this is an ancestral trait of ray-finned fishes.…”

Spatial changes in trace element and strontium isotope water chemistry in a temperate river system with application to sturgeon movement

“…Similarly, telemetry is often an inviable option when working with endangered species, as capture, surgery, and transmitter application may be harmful (Nielsen 1998;Godfrey et al 2003). Trace elements have been demonstrated to be a useful technique for identifying life history traits in sturgeons (Allen et al 2009(Allen et al , 2018a.…”

“…These techniques were found to be useful when identifying the spawning location, age determination, and growth of A. oxyrinchus oxyrinchus (Atlantic Sturgeon) (Stevenson and Secor 2000;Balazik et al 2012) and in A. brevirostrum (Shortnose Sturgeon) (Altenritter et al 2015). Strontium (Sr) isotopes, are also used to identify natal spawning areas of freshwater fishes (Hobbs et al 2007;Hobbs et al 2010), and contemporary studies have used them to distinguish freshwater movements of juvenile Gulf Sturgeon in the Choctawhatchee River System (Allen et al 2018a). Trace element and Sr isotopes analysis are potentially useful for other river systems occupied by Gulf Sturgeon, such as the Pearl River System in Louisiana and Mississippi where little is known of movements and habitat use of juveniles.…”

“…Identifying trace elements and strontium isotope gradients has the potential to provide useful baseline information for application to fisheries conservation within the Pearl River Watershed. Based on a contemporary study on the Choctawhatchee River System (Allen et al 2018a), it is anticipated that trace element and 87 Sr/ 86 Sr isotope ratios in calcified structures of fishes will be beneficial for life history reconstruction within the Pearl River System. This information is beneficial for resource managers for use in assessing changes within watersheds and identifying ontogenetic patterns, anadromous movements, and life history characteristics of Gulf Sturgeon and other fishes.…”