Regardless of the aquatic species an aquaculture venture produces, there are significant risks to su...
A Fish of Weedy Waters: Golden Shiner Biology and Culture
The golden shiner, Notemigonus crysoleucas (Mitchill), aptly described by Becker (1983) as a fish of weedy waters, is a major freshwater bait and forage species in the USA. This review summarizes key biological literature relevant to golden shiner culture, briefly describes historical production practices, and provides a comprehensive overview of the current commercial culture. Concise descriptions of golden shiner biology and habitat were provided by Hubbs and Cooper (1936), Scott and Crossman (1973), Becker (1983), Robison and Buchanan (1988), and Hill and Cichra (2005), among others. There have been several reviews of baitfish culture over the past decades (Brown and Gratzek 1980; Davis 1993; Stone et al. 2005), but most have not focused exclusively on the golden shiner. A significant portion of relevant literature is in older articles, theses, and dissertations or tucked within disparate studies on multiple fish species. Commercial golden shiner production methods have advanced considerably in recent years; yet decades-old publications are sometimes still cited as representative of modern farming practices. Examination of the biology and ecology of the golden shiner provides insight into traits that have made this fish of clear waters desirable for human uses and adaptable to pond aquaculture conditions.
Golden shiners are small fish with a thin and deep body, and a small triangular head (Fig. 1). Adults are typically less than 15–25 cm in length. The eyes are large, black spots within silver orbs, the mouth upturned, and the caudal fin is forked. From the top, golden shiners are drab olive in color, blending into the environment. In side view, golden shiners live up to their name, with bright silvery scales, at times with a golden cast. Scales are easily dislodged. Juveniles may display a dark lateral stripe. The lateral line is complete and strongly decurved (curving ventrally in the middle of the fish). A short, scaleless ventral keel extending from between the pelvic fins to the anal fin is a distinguishing characteristic. Breeding females may develop a yellow fringe to the pelvic fins, while those of breeding males become bright yellow, and the pectoral fins may become yellow as well. The abdomen of males becomes darker in color, with a sandpapery feel. The golden shiner's compressed fusiform body, subfalcate pectoral fins, narrow caudal peduncle, and deeply forked tail make it highly maneuverable, facilitating capture of mobile prey such as zooplankters (Keast and Webb 1966). Relative volume of swim bladder (8.0–8.5%) of golden shiners was found to be among the highest in 44 species of stream fish studied, reflecting its pelagic, quiet water habitat (Gatz 1979). As with other cyprinids, there are no teeth on the jaws, and a single row of pharyngeal teeth is used to crush food items against an upper bony plate. Cooper (1981) detailed the development of pharyngeal teeth in golden shiners from larvae to adult forms. The mouth gape is only 5% of the fish's standard length, but the mouth has a protrusible premaxilla and extendable mandible that form an effective scoop (Keast and Webb 1966).
FIGURE 1. Golden shiners (adults). Photograph by Anita Kelly
A description of the golden shiner would be incomplete if it stopped with the individual fish. The golden shiner is a shoaling species, forming loose aggregations of similar-sized fish and spending their lives in social groups (Pitcher 1983). Shoaling provides advantages in foraging and predator avoidance (Hoare et al. 2000) and has implications for fish culture, as shoaling behavior may restrict fish growth. Backiel and LeCren (1978) suggested that in temperate waters it would be natural for cyprinids and other schooling species to form dense populations with growth rates “well below the potential for the species.” The size of fish schools increases with fish density (Turesson and Brönmark 2007), so that relatively larger groups of fish would form in commercial culture ponds. Shoaling fish susceptible to predation should not stand out in the crowd, to avoid being targeted. Individual fish size and location within a shoal are influenced by the size of cohorts. Larger fish are typically found toward the head of the shoal and are selectively targeted by predators (Reebs 2001; Ward et al. 2002). Isolating an individual fish may increase stress levels. The improved swimming ability of golden shiners in groups as compared to individual fish (Boyd and Parsons 1998) appeared more likely to be owing to reduced stress rather than any hydrodynamic advantage. For a golden shiner, one is the loneliest number indeed.
The golden shiner is native to much of the eastern and central USA and southeastern Canada (Lee et al. 1980). The native range extends west to eastern South Dakota and fish found west of the Missouri River likely resulted from introductions (Bailey and Allum 1962). Golden shiners have been widely distributed by humans across the USA (Lee et al. 1980; Nico 2014). Introductions to California were made as early as 1891, and the California Fish Commission distributed golden shiners to multiple water bodies in the late 1890s (Dill and Cordone 1997). Whittier et al. (2000) found golden shiners to be “nearly ubiquitous” in northeastern US lakes, occurring in 71% of the 203 lakes sampled, and golden shiners were collected from 47 out of 60 Florida lakes sampled (Hoyer and Canfield 1994). Similarly, a survey of small, nongame fish species in Arkansas reservoirs found golden shiners to be one of the most widespread species, present in 40 of the 66 reservoirs sampled and found in all six ecoregions of the state (Buchanan 2005). In Nova Scotia, golden shiners were collected in 264 out of 744 lakes sampled (Alexander et al. 1986).
Use as Bait and Forage
Early 20th- century literature espoused the usefulness of golden shiners as a forage fish, especially for largemouth bass, Micropterus salmoides, and as a bait species. In 1931, Lewis Radcliffe, Deputy Commissioner of the US Bureau of Fisheries, declared: “The golden shiner (Notemigonus crysoleucas) is one of the best forage fish and bait minnows” (Radcliffe 1931). Clearly, the man knew his business; since that time, the golden shiner has been widely cultured and moved across the USA.
With their bright, shiny scales, golden shiners are popular fishing bait. Farm-gate sales of golden shiners were almost half of the total baitfish value in 2013 (Table 1). In 2013, 166 farms raising golden shiners were reported in 16 different states, with 74% of total sales by Arkansas producers. Roughly half a billion of golden shiners were sold in 2013, approximately 2.77 million kg, at a reported average price of $5.16/kg ($2.34/lb) (NASS 2014b). However, the typical wholesale farm-gate price of golden shiners in Arkansas is nearly double this figure, around $9.37/kg ($4.25/lb). In the Midwestern USA, golden shiner wholesale price is $19–$22/kg (Tye 2013). Thus, the reported 2013 farm-level value of the US golden shiner production ($14.3 million) may be an underestimate if price/kg was used to calculate value. The total retail value of golden shiners is not known, but may be roughly two to five times that of the wholesale value (estimated from Meronek et al. 1997a, 1997b). Tye (2013) reported retail prices in the Midwest for medium golden shiners to be $6–$10/dozen. Freshwater anglers spent over $950 million on bait (excluding artificial lures) and $43.5 million on baitfish harvesting and holding equipment in 2011 (USFWS 2011).
Golden shiners are also used as supplemental forage for largemouth bass and other predatory fish. In northern states, they may be stocked in small impoundments as the primary forage base in place of sunfish, Lepomis spp. Golden shiners have long been used as forage for bass broodstock in rearing ponds (Hubbs and Cooper 1936), although their propensity to feed on bass fry was also documented (Cooper 1935; Surber and Klak 1939). They are stocked as a supplemental forage fish in the southern region despite their reputation as egg eaters (Stone 2008). Nell et al. (1939) described watching golden shiners surround a largemouth bass nest, and while the bass was looking away or chasing some of them, others would dart in and seize eggs. Sunfish are widely recommended as the forage fish to stock in combination with largemouth bass in small impoundments, but golden shiners can also be used, although populations may not be self-sustaining (Swingle 1949; Regier 1963). In the south, golden shiners spawn in the spring and few, if any, grow large enough to escape bass predation (Swingle 1949), whereas they will spawn throughout the summer in northern states (Regier 1963). Tilden (1929) suggested that an association of largemouth bass and golden shiners with filamentous and planktonic algae would be worthy of study in the midwestern states. The combination of largemouth bass and golden shiners remains a recommended option for cool or warmwater ponds in some northeast states (Eipper et al. 1997; Dauwalter and Jackson 2005).
Golden shiners can reach 30 cm in length (Page and Burr 1991) but are not normally considered a food fish. Nevertheless, the golden shiner was among fish species caught and putatively consumed by Harvard College students in 1651–1674 (Singer 1982), during a long-lost epoch when food was a far greater college expense than Harvard tuition (Foster 1959). Forbes and Richardson (1908) noted that the golden shiner “is said to be an excellent panfish, if of sufficient size.” Golden shiners have also been used as experimental fish in bioassays (Hauser 1984) and in numerous studies on collective behavior (Krause et al. 2000; Reebs 2000). Results of such studies may have implications for human behavior (Couzin et al. 2011). In some cases, results have implications for aquaculture. That fish gather in anticipation prior to feeding time (Reebs and Gallant 1997) or can learn where feed is supplied at different times (Reebs 1996) are perhaps obvious to a fish farmer. More useful is the fact that minnows tend to shoal with similar-sized fish (Pitcher et al. 1986; Reebs 2001), so care must be taken when sampling fish in ponds to collect a representative sample. In small experimental ponds, this typically requires seining the whole pond. Interactions of golden shiners with robotic fish have also been examined (Marras and Porfiri 2012; Polverino et al. 2013). One waits for a robotic decoy to lead fish into harvest nets.
Golden shiners are members of the minnow family Cyprinidae. Interestingly, it is the only species in the genus Notemigonus and appears more aligned with European cyprinids than most other North American minnows. Ancestral golden shiners likely first showed up on the North America continent in the early Miocene, crossing from Europe (Perea et al. 2010). Fossil records are limited; a fossilized pharyngeal arch thought to belong to a golden shiner was excavated from Pleistocene deposits in western Oklahoma (Smith 1954). In the past, at least three subspecies were identified based on differences in anal fin ray counts, but this trait was found to vary with water temperature during development and currently only one species is recognized (Lee et al. 1980). Hubbs (1926) noted a linear decline in the number of anal rays (from 15 to 11) in golden shiners as one moved north from Florida to Minnesota, with “…a decrease of one ray taking place each four hundred miles.”
The European rudd, Scardinius erythrophthalmus, is very similar in appearance to the golden shiner, but has scales on the ventral keel, and the fins are red when in breeding color (Schofield et al. 2005). The rudd was initially introduced into the USA in the late 1800s or early 1900s and was cultured as a baitfish in Virginia (1970s) and Arkansas (1980s) (Fuller et al. 1999) before this use was prohibited. Few large populations of rudd are currently found in the USA, with the exception of Buffalo Harbor in Lake Erie and the upper Niagara River (Kapuscinski et al. 2012b). Food habits of the rudd appear similar to those of the golden shiner although relatively greater amounts of vegetation are consumed, especially in the summer (Kapuscinski et al. 2012a, 2014). In the Discussion section of Hubbs (1933), Embody (New York) reported on rearing the European pearl roach (rudd) as a forage fish. Hubbs' prescient response: “I would like to raise a question as to the advisability of rearing in our waters fish like the pearl roach, European fish of unknown capacities. We should keep in our minds the fact that there is danger in introducing exotic species, especially if there is some native species which reasonably can be expected to take their place.” Sax et al. (2007) listed among classic insights on ecological invasions, that reproductive isolation “can take millions of years.” The ability of the golden shiner to interbreed with the rudd was cited as an example. Using hormone injections, Burkhead and Williams (1991) were able to induce natural spawning and produce viable rudd female × golden shiner male hybrids; the reciprocal cross produced few eggs and no surviving larvae. Both species were found to have 50 chromosomes, but substantial differences in their karyotypes suggested that the hybrid might be reproductively impaired or sterile (Li et al. 1991). Additional studies confirmed that under hatchery conditions both hybrid crosses could be made naturally and viable offspring obtained, but no spawning behavior was observed or offspring produced in attempts to spawn the F1 hybrids (Tave et al. 1993; Goodwin et al. 1994). Thus, it is not clear if the hybrids can successfully reproduce or not.
This "Editor's Choice" article is an exerpt from the full article. Read the entire article in the April 2016 issue of JWAS here
About Nathan M. Stone, Anita M. Kelly and Luke A. Roy
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