Gilled tubificid worm

Branchiura sowerbyi is a freshwater benthic deposit feeder that prefers rivers and warmer waters. This species prefers muddy substrate but has been recorded in a variety, including silt-sand, organic matter, and coarse detritus (Liyanage et al. 2003; Perova 2022). B. sowerbyi is adaptable and demonstrates a broad tolerance to water temperature, oxygen concentration, water body type, and water level fluctuation in introduced ranges (Brainard 2018; Yan et al. 2021; Georgieva et al. 2022). See the table below for environmental tolerances reported by Fofonoff et al. (2020):

Food Web

Branchiura sowerbyi is a benthic detrivore that feeds upon organic matter in the sediment along lake or river bottoms (USACE 2024). This species burrows into the sediment to feed (up to 20 cm depth), mixing the sediment and leading to bioturbation (Brainard 2018; Mychek-Londer 2018). B. sowerbyi feeding mobilizes solutes in the sediment, introduces buried organic material to the water column, and its recycling rates are reportedly higher than any other freshwater oligochaete (Wang and Matisoff 1997; Matisoff et al. 1999). Oligochaetes are a prey item for benthivorous fish and predatory invertebrates: likely predators of B. sowerbyi in the Great Lakes includes both native (i.e. whitefish Coregonus clupeaformis) and non-native species (i.e. common carp Cyprinus carpio) (Fofonoff et al. 2020).

Life History

Branchiura sowerbyi has a life expectancy of 1 to 2 years, depending on habitat conditions (Carroll and Dorris 1972). Similar to other oligochaetes, B. sowerbyi is a hermaphrodite that reproduces sexually or asexually through fragmentation, asexual reproduction is the most common (Highnam 1977; USACE 2024). Individuals can reach sexual maturity within 4 months and breeding is reportedly restricted to the warmer months but two reproductive cycles have been observed in optimal conditions (Lobo and Alves 2011). Temperatures between 10-32.5 ºC are required for reproduction (Fofonoff et al. 2020). B. sowerbyi’s tolerance to environmental conditions and broad distribution suggest it is able to adapt its life cycle to local conditions (Carroll and Dorris 1972).

Summary of species impacts derived from literature review. Click on an icon to find out more...

Environmental	Socioeconomic	Beneficial

Branchiura sowerbyi  is a conveyor-belt feeder that mixes benthic sediments, bringing deeper sediments to the surface (Matisoff et al. 1999; Brainard 2018). Because it is larger than other freshwater oligochaetes, B. sowerbyi can burrow deeper into sediment (up to 20 cm), homogenize layers at a greater depth, and transport large amounts of benthic materials to the sediment-water interface (Matisoff et al. 1999; Mychek-Londer 2018).

Branchiura sowerbyi, with other oligochaetes, has been documented as a host of myxosporean parasites which cause fish pathogens such as swim-bladder disease and haemorrhagic thelohanellosis in Asia and Europe, and its presence has been correlated to high levels of infection in fish (Liyanage et al. 2003). B. sowerbyi is an intermediate host for Thelohanellus kitauei, a parasite that causes intestinal giant cystic disease in common carp Cyprinus carpio (Zhao et al. 2016). Several novel parasites have been reported infecting B. sowerbyi in China (Liu et al. 2020; Liu et al. 2022a; Liu et al. 2022b; Liu et al. 2023).

There is little or no evidence to support that Branchiura sowerbyi has significant socio-economic impacts in the Great Lakes.

Branchiura sowerbyi has the potential to negatively impact fish farms due to its role as an intermediate host for the parasite Myxobolus lentisuturalis. This parasite has been observed infecting goldfish at a commercial farm in North Carolina (Hepps Keeney et al. 2023).

Branchiura sowerbyi has a moderate beneficial impact in the Great Lakes.

Branchiura sowerbyi, due to its high productivity and ease of cultivation, has potential to be utilized as a food source for fish farming (Lobo and Alves 2011). Specimens are easy to handle and can be used in ecotoxicological studies (Ghosh and Konar 1983; Marchese and Brinkhurst 1996; Das and Das 2005; Saha et al. 2006; Lobo and Espíndola 2016). B. sowerbyi burrowing and subsequent bioturbation reduces methane (CH4) emission to the atmosphere by increasing methanotrophic activities in the soil (Mitra and Kaneko 2017).

Regulations
There are no known regulations for this species.

Note: Check federal, state/provincial, and local regulations for the most up-to-date information.

Control

Branchiura sowerbyi has not received much attention regarding control studies. The effects of industrial toxicants on Tubificidae species and explorations of their value as an indicator of environmental quality have been explored, but chemicals and heavy metals are not viable methods of control because of unknown and adverse effects on the surrounding environment (Das and Das 2005, Saha et al. 2006; Saha et al. 2020; Sarkar et al. 2022). However, there has been investigation into the control of Branchiura sowerbyi as a host of haemorrhagic thelohanellosis, which negatively impacts fish in aquaculture (Liyanage et al. 2003).

Biological

Brown trout, Salmo trutta L., has been shown to prey on oligochaetes; its removal from an experimental environment led to rapid multiplication of benthic fauna (Wahab et al. 1989). However, brown trout is itself an invasive species in the Great Lakes region and across nearly all of the United States (Fuller et al. 2013).

Physical
Researchers found that Branchiura sowerbyi, which is a vector in transmission of Thelohanellus hovorkai (myxozoa) to fish, prefers muddy substrate, while other benthic oligochaetes that are not susceptible to myxozoa prefer sandy substrate, and suggested that replacing bottom substrate from mud to sand would lead to a shift in oligochaete communities from Branchiura sowerbyi  to non-susceptible oligochaetes such as Limnodrilus socialus, therefore reducing disease in aquaculture fauna (Liyanage et al. 2003).

Chemical
While there are no known chemical controls specifically for Branchiura sowerbyi, declines in Oligochaeta in southern Lake Michigan were recorded between 1980 and 1993 in correlation with reductions in phosphorus loads (Nalepa et al. 1998), suggesting that reduction of excess nutrients would help to reduce oligochaete populations.

Note: Check state/provincial and local regulations for the most up-to-date information regarding permits for control methods. Follow all label instructions.