Modeling White Sucker (Catostomus commersonii) populations to assess commercial harvest influence on age structure

Figures & data

Figure 1. Conceptual model for White Suckers. Stock-recruitment relations were simulated using either Ricker or Beverton-Holt recruitment processes. Each box represents an age-class, YOY is young of the year, S is survival, I represents non-reproductive individuals, P represents probability of maturing at a given age, X represents mature individuals, Eggs is the total number of eggs produced in a season from each mature age-class, and END limits White Sucker life expectancy to 21.

Table 1. Parameters used in the population model for White Suckers in Maine. Equations are provided and explained in the Methods section.

Variable	Value	Source
Fecundity:
a	0.5214	1
b	1.7541	1
Length at age (age-3 to 21):	201–473 mm	1
Recruitment to YOY:
α	0.0035	2
Ricker-β	2.660 × ${10}^{-8}$	3
Beverton-Holt- β	1.717 × ${10}^{-7}$	3
Probability of spawning (P):
PAge-3	0.20	–
PAge-4	0.30	4
PAge-5	0.60	4
PAge-6 to PAge-21	1.00	4
Probability of sequential spawn:	0.65	5
Natural mortality (M)
YOY	0.97	6
Age-1	0.97	1, 6, 7
Age-2 to 21	0.25	1
Fishing mortality (F)	0.00–1.00	–

¹Begley et al. (2017),

²calculation using data from Johnson (1975) see methods,

³MDIFW unpublished data on Little Moxie Pond White Sucker removal project,

⁴Wakefield and Beckman (2005),

⁵Geen et al. (1966),

⁶McPhee (2007), and

⁷Miller et al. (2013).

Figure 2. Comparison of actual and model data age structures of White Sucker populations (a) closed to harvest and (b) open to harvest. The field data in panel A consist of three unfished lakes combined, and the field data in panel B consist of three fished lakes combined (F = 0.466; see Begley et al. 2017). Gray bars represent actual data, black bars represent model data.

Table 2. Sensitivity (S_e) analysis of White Sucker population density after a 1% increase in the α-parameter, β-parameter, natural mortality (M), fecundity function constants (a and b), and probability of recruitment to spawning for young spawners (P_Ages4-6). Sensitivities were run for both the Ricker and Beverton-Holt recruitment curves. E_T represents the total number of eggs produced in a spawning season, YOY is recruitment to six months, and Spawner is total number of predicted spawning adults.

Density	α	β	M	Fecundity (a)	Fecundity (b)	Spawning PAges4-6
Beverton-Holt
ET	1.069	−0.987	−2.333	1.038	11.217	0.128
YOY	1.079	−0.965	−0.093	0.077	0.521	−0.052
Spawner	1.077	−0.977	−1.986	−0.287	0.523	0.250
Total population	1.079	−0.964	−0.950	0.073	0.519	−0.054
Ricker
ET	0.339	−0.999	−0.714	0.334	3.356	0.061
YOY	0.309	−0.974	1.449	−0.675	−6.605	−0.124
Spawner	0.319	−0.992	−0.407	−0.663	−6.591	0.178
Total population	0.310	−0.980	0.594	−0.681	−6.597	−0.130

Figure 3. The age structure of a White Sucker population post harvesting (F) using the Ricker (a) and Beverton-Holt recruitment models (b).

Figure 4. Modeled change in the biomass (kg) of White Suckers harvested under varying levels of additive mortality (F = 0.00 to 1.11). Solid line represents the biomass of fish harvested at the first year of harvest for both the Beverton-Holt and Ricker models. The long dashed line represents the amount harvested after values stabilized in the Beverton-Holt model, and the small dashed line represents the amount harvested after values stabilized in the Ricker model.

Begley M, Coghlan S, Zydlewski J. 2017. A comparison of age, size, and fecundity of harvested and reference White Sucker populations. N Am J Fish Manag. 37:510–523.

 Web of Science ®Google Scholar

Johnson F. 1975. Interspecific relationships of Walleye, White Sucker and associated species in a northeastern Minnesota Lake with an evaluation of White Sucker removal for increased Walleye yield. Minn Dept Nat Res Div Fish Wildl Sect Fish Investig Rep. 338:2–49.

 Google Scholar

Wakefield C, Beckman D. 2005. Life history attributes of White Sucker (Catostomus commersonii) in Lake Taneycomo and associated tributaries in southwestern Missouri. SW Nat. 50:423–434.

 Web of Science ®Google Scholar

Geen G, Northcote T, Hartman G, Lindsey C. 1966. Life histories of two species of Catostomid fishes in Sixteenmile Lake, British Columbia, with particular reference to inlet stream spawning. J Fish Res Board Can. 23:1761–1788.

 Web of Science ®Google Scholar

Miller D, Tietge J, McMaster M, Munkittrick K, Xia S, Ankley G. 2013. Assessment of status of White Sucker (Catostomus commersonii) populations exposed to bleached kraft pulp mill effluent. Environ Toxicol Chem. 32:1592–1603.

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