Juvenile Salmon Survival in the Saint John River System

W. D. Watt and G. H. Penney

Freshwater and An ad romous Division Resource Branch Department of Rsheries and Oceans Halifax, Nova Scotia

May , 1980

The Huntsman Marine LaboratOrY

Canadian Technical Report of Fisheries and Aquatic Sciences No. 939

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Canadian Technical Report of Fisheries and Aquatic Sciences No. 939

May, 1980

JUVENILE SALMON SURVIVAL IN THE SAINT JOHN RIVER SYSTEM

W.D. Watt and G.H. Penney

Freshwater and Anadromous sion Resource Branch

Department of Fisheries and Oceans Halifax, Nova Scotia

B3J 2S7

~ Minister of Supply and Services Canada 1980 Cat. No. Fs 97-6/1980-0939 ISSN 0706-6457

iii

CONTENTS

LIST OF TABLES ..... v

LIST O.F' ILLUSTRATIONS . v ~ -"

ABSTRACT/RESUME . i

INTRODUCTION. . 1

METHODS AND RESULTS .

DISCUSSION. 4

CONCLUSIONS 5

REFERENCES. . 13

TABLE 1. Numbers of wild

LIST OF TABLES

salmon counted facilities

estimated ) composition of

v

at the Mac during the (from scale the various ups . . . . . . . . . . . . . . . . 2

TABLE 2.

TABLE 3.

TABLE 4.

TABLE 5.

FIG. l.

FIG. 2.

FIG. 3.

FIG. 4.

FIG. 5.

Nrunbers of salmon and lse in spawning escapements above Mactaquac Dam during 1967-77 and es egg depositions ( per 1 0 0 m 2 ) • • • • •

Actual returns to Mactaquac wild virgin salmon progeny from spawning years 1967-72 . . . ..... .

Total potential returns to Mactaquac for spawning years 1967-72 ..... .

Tob salmon spawning escapement and estimated egg deposition ...... .

LIST OF ILLUSTRATIONS

Saint John River system map, indicating positions of dams and some major tributaries . . . . . . . . . . . . . . . .

Total ac returns to wild vi n salmon and years 1967-72 vs. above Mac

of from spawning

den

Es re ve dis (%) of wild salmon grilse returns among the harvesters, actual returns counted at

Total po al returns to of wild virgin salmon and lse from spawning years 1967-72 vs. egg-deposition density above Mactaquac .

Actual and returns to Mactaquac per 8,000 eggs (one salmon) of wild virgin salmon and gr se progeny from spawning years 1967-72 .......... .

2

2

3

4

vi

7

8

9

. . . 10

FIG. 6 . 1 returns to Mac of wild virg sa and grilse years 1967-72 vs. est densi 11

ABS'I'HAC'l'

tt, W.D. and G.H. Penney. 1980. Juvenile salmon survival in the Saint John River system. Can. Tech. Rep. Fish. Aquat. Sci. No. 939. vii + 13 p.

For the Saint John Hivc~r system above Mactaquac Dam the number of actual v1n;in returns per female salmon spawner rose from 10 ( 8, 000 eggs) for SjXHvn year 1967 to a peak of 16 for 1969 and then to 3 for 1972. Most returns were in the fourth, ifth and sixth This

and decline is attributed t:o a combination o poor juvenile survival (ciue to ) in the main stem of the Saint John River and to changes

the proportions of spawning adults released into the main stem and into the Tobique River (a tributary). The adult· return for sal-mon spawners in 'l'obique River was high ( 16.8 per 8, 000 eggs), for fish released into the main stem (Woodstock) and not migrating to the 'l'obique, the return rate was not significantly greater than zero (2.8 per 8,000 eggs) To maximize the number of wild salmon returns, it is recommended that t.he

rst priority should be to ensure an adequate egg-deposition density in Tobique River.

Key words: Atlantic salmon, Saint John River syst.em, Mactaquac Dam, Tobique Hiver, juvenile salmon survival, rearing habitat, egg-deposition density, water _quality.

RESUME

'datt, W.D. and G.H. Penney. 1980. Juvenile salmon survival in the Saint ,John River system. Can. Tech. Rep. Fish. Aquat. Sci. No. 939. vii + 13 p.

Pour le system fluviale de la riviere Saint-Jean en amont du barrage de Hactaquac le nombre de saumon reproducteurs vierges, issue de chaque femelle en fraye, s'est accru a de 10 (pour 8,000 oeufs) en 1967 jusqu'a atteindre un sommet de 16 en 969 et decliner j 3 en 1972. La pluspart des saumons reproducteurs qui retournerent a frayere d'origine au cours de ces annees de reproduction etaient ages de quatre,

ou six ans. Cet accroissement et le declin suivit sont attri-a l'effet combine d'une mauvaisf~ survie ( cause de la pollution)

des saumoneaux dans le tronc principale de la riviere Saint-,Jean et aux changements dans les relatives des saumons reproducteurs liberes dans le tronc de la riviere Saint-Jean et dans la riviere 'I'obique ( tributaire de La moyenne des

issue des saumon de la riviere pour 8,000 oeufs), que pour les saumons

dans le tronc principale (Woodstock) et qui n'emigrerent pas dans riviere 'l'obique, le taux de retour ne fut pas significativement plus grand que zero (2.8 pour 8,000 oeufs). La "maximisation" du nombre de saumon reproducteurs natifs que l'on donne priorite a la ition d'oeu£ en densite suffisante dans la riviere Tobique.

vii

N

1

Dam

Beechwood Dam NEW BRUNSWICK

MAINE

Mactaquac

km

FIG. l. s John River system map, indicating positions of dams and some major tributaries.

all an~:1drornous

John River (past

l NTHOIJlll "['I ON

of the

counted and sorted at the Mactaquac fish­handll facility, and from here they have been rried in tank trucks to various

lease points. Atlantic salmon most part, trucked either to at Woodstock or to the

tributary (Fig. l) .

S lmon leased at Woodstock have a choi of spawning sites they may remain in the main stem, enter the Becaguimec River some other small tributary, or pass over the fish lift at Beechwood Darn. Above Beechv10od they may remain in the main stem between Beechwood and Grand Falls, pass to Salmon River or some other small tributary, or pass up through the fish ladder at Tobique Narrows Darn on the rrob H1 ver ~

areas o access1ble juvenile sal­mon rearing habitat available above Mactaquac Dam are distributed as follows:

River sect.ion

Beechwocx:1 Darn to Grand Falls

Other accessible

'I'otal

i::stimat<c'<l rearinq habitat

(Units of 100 m2 )

41,810

25,080

94,440

11,950

173,280

Percent

24.1

14.5

54.5

6.9

100.0

Of the accessible tributaries other than

(from Woodstock) the Tobique, the

are the Salmon best for salmon and which are es ted

5, 100 and 4, 0 juvenile Atlantic sal­

mon rearing habitat. A number of other small tributaries contain minor quantities of rearing habitat (approximately 2,650 units in all).

Atlantic salmon management policy on the Saint John River has attempted to maxi­mize salmon production by aiming for a potential egg deposition in all accessible habitat of 240 eqgs/100 m2 as recolnJ11ended by Elson ( 1957)

1 The history of hydroelectric develop-on the Saint John River and the inter­

ac~ s of these developments with aquatic ecology and fisheries have been described by Ruggles and Watt (1975).

M1':'1'l!O!JS /\NU HESULTS

Upstream migrating anadromous f sh sorted (species) in the fish­

at Mactaquac Dam, and then all Atlantic salmon are carried tank truck to the salmon-sorting facil ty at Mactaquac Hatchery.

and continuing to and life history of

lse returning to Mactaquac have determined read-ings of scale samples ('l'able l) . Data from returns of hatchery releases were not used in this analys The wild-indicate that uvenile salmon in the Saint John River smoltified after 2 (49.1%), 3 (49.3%) or 4 (1.6%) fresh water. The adults returned a one year at sea as grilse (39.2%), or after two sea-year·s (51.4%) or three sea-years ( .2%) as virgin salmon. Also, on average, about 9.2% of the total were repeat spawners (non-virgin salmon) .

Most virgin returns (98.2%) were in the life-history categories 2:1 (i.e., 2-year-old smolt~ and one at sea, 8.9%), 3 : l ( 2 3 . 6% ) , 2 : 2 ( 3 0 . 1% and 3 : 2 ( 2 5 . 6% ) . Thus, most returns come in the fourth, fifth and the largest ring in the 2:2 salmon return

depositions in the Sain John River Mactaquac Dam for the 1967-77 have been estimat.ed (Table ratios for estimation of tential deposition were taken as overa from a data series (1967-77) of vi sexing of the data

qrilse. For was assumed 8,000 eggs/fish (1,80 grilse produce 3,200 apparent (Table 2) that gr ponent, because of the small fish size and low proportion of females, relative insignificant eggs to total spawning.

The fish-return data (Table ) can be used to as the various life-history classes to spawning year. This arrangement (Table 3) allows comparison of the total annual returns to of

tion densities for the river system (Fi . 2) . 'l'he shape of

suggests a curved line, which could be lower sur·vi val at sity of 1972. However, density is (1957) recommended s/ 100m 2 • When a least squares straight

"', Nwnl.Jer:~ of wild qr.ilse and sal_mon counted at the Mactaquac fish-passaqe fac;i1ities rs 1972 78 a11d estimated (from scale readings) composition of the various age

groups.

TABLE 2. Nwnbers of salmon and gri1se in spawning escapements above Mactaquac Dam during 19 7- 7 estimat.ed egg depositrons (per 100 m2 ). (The numbers have been corrected for the reported angling catch. The juvenile habitat accessible above Mactaquac is taken as 17,328,000 m2 .}

---------- ------~

'l'ot,al Year eggs/100 m"

--------

196 7 487 18.6 682 0. 9 19.5 1968 12 3 4. 7 954 1.3 . 0 1969 640 24.5 1,885 2. 6 2 7. l

970 1,219 46.7 2,445 3. 0.0 1971 1,383 52.9 1,425 . 9 . 8 19 2 16 177.2 7 • 0 178. 1973 2,305 88.2 2,978 4 .l 92. 19 74 5, 0 J 19 3. 0 6,142 8.4 20 1975 7, 271 278.3 9,629 3.2 :!9 . 5 l 6 6,003 229.8 12,578 17.2 47.0 l 77 7,562 289.4 7,339 10.0 299.

TABLE 3. Actual returns to Mactaquac of wild virgin salmon progeny from spawning years 1967-72.

Spawning year 2:1--

1967 688i 596 37 1,260 1968 110 404 34 549 1969 1,413 1,762 57 3,806 1970 1,593 3,727 177 3,566 1971 1,941 2,658 39 2, llO 1972 3,962 2,545 33 4,236

~Number estimated from average proport.ion.

1,551 0 0 377 35 0

2,208 31 84 2,999 0 37 1,858 0 67 1,817 15:1 571

Total actual return

'132 1,509 9,361 1,209 8' 6 73

12,665

l '-S fitted to these data (Y'''S, 340 + 49. Sx), theY- intercept is not signi-f cantly .05) greater than 0, as it shoul be f the relationship were s1gnificantly curved. Also, when fitted with a second-order polynomial, the curved

inc is not a significantly better fit than the straiqhi line; hence it must be concluded that-the apparent reduction in survival of the 1 72 eq9s is not signifi­cant.

'l'he returns presented (Tables J and 3) are o fish that have escaped capture by commercial fishennen (i.e., incidental catches, since the commercial salmon f1shery has been closed since 1972) , poachers, the Indian food fishery at Kingsclear and anglers. Estimates of the relative (percent) impact on wild

returns by the various in the harvesting are

(Fig. 3) . The values for angling catches have been derived from reported catches (New Brunswick Fish and Wildlife Branch); catches in the Indian food fishery have been estimated from observations; and the combined levels of poaching and incidental catches in commercial gear set for other species have been roughly esti­mated at about 10% for the years 1972-75 and 20% for the years 1976-78.

Since the closure of the commercial salmon fishery in 1972, the proportion of the salmon run reaching the Mactaquac fish­handling facilities has steadily declined as a result of increased harvesting by the Indian food fishery, and incidental com­mercial catches and poaching. The propor­tion of the salmon run taken by anglers has remained fairly constant. The grilse returns show a similar exploitation trend, with the exception that the proportion taken by the Indian food fishery is lower than for salmon.

Total potential returns (Table 4) were computed by applying the approximate cor-

rection values (above) for each return year to the actual return data (Table 3) A plot of these total potential returns for each spawning year versus the esti­mated egg-deposition curve (Fig. 4) which appearance to the actual returns ( a diminished rate returns in the year 1972 is (Fig. 4). Hmvever, as was shown with the curve for actual returns (Fig. 2) , the apparent reduction survival s not statistically significant.

It is common to consider changes in survival rates in terms of returns per spawning female. A female salmon lays approximately 8,000 eggs (3,200 for a female grilse). Accordingly, the return rates (actual and potential) per 8,000 eggs deposited above Mactaquac Dam are depicted (Fig. 5). 'rhis histogram indi--cates that survival between 1967 and 1969 and then during 1970-72.

It was initially considered that this trend probably represented mortality problem in downstream fish due to changes in turbine However, an hydropower generation and development yields nothing that could account for the trend. Possible changes in smo1t predation rates (eg , by chain pickerel) have lso been considered and discounted. The known factor that to parallel survival-rate the proportion of the egg deposition in the •rob Ri. ve (dashed line in l"i.g. 5). The variation in returns per 8,000 would be largely accounted for if uvenile salmon survival ) were substan better for spawned in Tob than for fish spawned elsewhere Saint John River system.

To test this hypothesis urther,

TABLE 4. returns to Mactaquac for 19 7-72. ac 1 returns plus e of the numbers of fish taken Indian food fishery and anglers) .

Potential returns Spawning year

1967 1968 1969 1970 1971 19 72

8001. 128

l' 6 37 1,935 2,275 5,487

6 89 469

2,141 4' 38 3 3,680 3,857

43 41 67

245 58 57

1 '4 36 652

4, 871 4,515 4,375 8,521

1,843 4 82

2,794 6, 2 31 3,737 5,143

----------------------------------------------------------'·Number estimated from average proportion.

0 4

65 0 0

421.

fishermen, poachers, the

0 0

174 74

190 1581.

'I'otal potential return

4' 811 J.,816 1,749 7 f 3 8 3 4,315

23,265

Dep:Jsihon Year of egg;/100 m2

379 13.5 78 352 6.

1969 593 ,572 45.6 1970 932 1,850 70.1 1971 1,166 738 83.7 1972 2,140 150.9 197 3 88.8

3, 728 257.8 1975 6, 722 369. 1976 7 O"C ,~..L:J

1977 ,305 325.

system usive o not is-

tical regressions on egg deposition in river sec-tions from Woodstock to Beechwood and from Beechwood to Grand Falls are also not significant.

To estimate from spawners in in the int John main tributaries (above simultaneous

urviva River and those

of

t

H turns to

s

DISCUSSION

John Fiver, where water quality Wi:lS suit­able for spawning activities in October­November but unsuitable for juvenile­salmon survival during the mid-summer low-flow periods (Environment Canada 1973). Moreover, water toxicity have been reported by MacDonald et (1970) and Dominy (1973) in main stem Saint John River lvater at the Mactaquac salmon hatchery (usually during high spring flows).

Fish spawning in the smaller tribu­taries (Salmon, Becaguimec, etc.) would encounter suitable water quality, and these tributaries should be capable of providing at least a small proportion of the wild­salmon run. Unfortunately, it is impos-sible at to sort the adult fish according to ir tributary of origin. Inevitably, fish from other tributaries were released in Tobique River and most of the fish released at Woodstock were Tobique River fish, and thus less inclined to spawn in any of the other tributaries.

Even so, some spawning must have taken place at least in the Becaguimec River, whose confluence is near the Woodstock release site. Electrofishing results (available since 1972) do indicate reason­ably high juvenile populations in this tributary (Francis 1980). However, the entire juvenile-salmon rearing area avail­able in the Becaguimec River is equivalent to only about 41 of the rearing area in the Tobique River. Hence even if this tributary was producing to capacity, its contribution could not significantly alter the trends (Figs. 5 and 6).

The smolts from the Tobique River tributary have to pass through three headponds (possible predation) and over three power dams (possible spillway and turbine mortality) in their seaward migra­tion. The possibility of increased down­stream fish-passage mortali was initially advanced to explain the off in return rates to t-lactaquac (Fig. 5). However, the high return rate for fish spawned in the River virtually rules out any unusually high rates of downstream mortality.

In spawning years 1971 and 1972, small numbers of hatchery-reared returns were included among the potential spawners released at Woodstock and Tobique. There is evidence (unpublished) that the migra­tory behaviour of these hatchery fish is rather different from that of wild fish, and thus there is some question as to their comparability in terms of potential

deposition. The numbers involved were % of salmon in 1971 and ll% in 1972, and

the inclusions might have caused slightly reduced survivals in these years. The effect, if present, does not appear to be statistically significant.

The data points in Fig. 6 suggest that the relationship between deposi-tion in the Tobique River and returns to may actually be curved, but is not significant (p>O.OS). However, at higher egg-deposi-

tion densities, the lope will inevitably flatten out. Elson (1957) suggested 240 eggs/100 m2 as near optimal for Maritimes salmon rivers. Elson (1975) has revised the figure downward to about 170/100 m2 •

Symons (1979) considers that the relation-ship between smolt and deposition density vary age at smoltifi.cation. Thus a river producing smol ts would require a lower ity for maximum smolt production would one producing 3-year-old or 4-year-old smolts. On this basis, a river such as the Saint John (Tobique) which produces roughly half and half 2- and 3-year-old smolts can be expected to approach maximum smolt pro-duction at a density 150-200 eggs/100m 2 • Tobique River may already have reached its maximum tion in 1972 at an egg density 100m2 •

In any case, egg densities consider­ably in excess of this theoretical (Table 5) occurred in Tobique River 1975-77. Returns from these years (expected in 1981-83) a fitted curve which calibrates Tobique River for optimum smolt production.

CONCLUSIONS

1. The adult-return potential of fish

2.

3.

4.

5.

released in or success into the Tobique River is (averaging 16.8 ± 1.0 returns per female salmon) .

The adult-return potential for fish released at Woodstock and not migrat­ing into the Tobique River is low ( 2. 8 ± l. 8 ret.urns per female) .

To maximize the number of wild mon returns to Mactaquac, the t priority should be to

egg-depos River ( as

0 6 eggs or about salmon spawners).

The rise and decline in salmon ret. urn rates to Mactaquac for spawning 1967-72 is attributed to of poor juvenile survival (due to pollution) in the main stem of the Saint John River and changes in the relative of returning adults the main stem and into Tobique Hiver.

The evidence suggests that Saint John River tality during the migra-tion is not unusually high.

14

--·1972

12 01970 ........ (I')

'0 c: (1:1 (I')

:J 10 0

.c - o1969 ....... (I')

Cl 1971 c: ... :J

8 -G) ... (1:1 :J -0 (1:1 6 (1:1 .... 0 1-

4

2 01968

0~----------------~---------~--------~---------------~--~----------------~

0 100 150

Eggs r 100m 2 above Mactaquac

FIG. 2. Total actual returns to Mactaquac of ld virgin salmon and grilse from above Mactaquac. spawning years 1967-·72 vs. e sit dens

8

c 0 E ccs (/)

-0 -I-' c (J) (.) I.-(J)

a..

Angling

In dian food fishery

Incidental catch and poaching

Actual returns to Mactaquac

Angling

Indian food fishery

catch and poaching

Actual returns to Mac taq uac

0~~---L~----L------L------L------L~~~ 19 76 1977 i 978 1972 1973 1974 1975

n a

FIG. 3. Es salmon and grilse returns and actual returns

25

e1972

-Cl)

"C c 20 C'O Cl)

:s 1970 0 • .r::. --(/)

15 c ... • 1971 :s -(I) ...

• 1969 C'O -10 c (I) -0 a.

5 e1967

e1968

QL-----·-------------~------------------~----------------~----------------~ 0 50 100 150 200

Eggs r 100m 2 above Mactaquac

FIG. 4. Tota 1 returns to Mactaquac of wild virgin salmon and grilse from spawning years 1967-72 vs. egg-deposit.ion density above Nactaquac

10

Correction for , Indian fishery, poaching and incidental catches

return rate 100

0--0 Tobiqlle River 0 I \

I ' I \ \

I \ I \

I \ 0 I \ _," I

20 I \ ,; I 8 I \ ,;

I "' I \ "' .. I

I 0 I I I

I \ I I

I \ I \

I I

I \ I \ (j) I \

01 I \ I \

01 15 I I 60 I Q) \

I I

0 I \

0 I \

0 I I

co I \ I 0 !... I (])

0.10 40 (j) 0 c !...

::::J +-' Q) rr

5 2

oL-~-L~~~~~--~~~--~~~~o 1967 1968 1969 1970 1971 1972

Spawning year

FIG. 5. Actual and potential returns to Mactaquac per 8,000 eggs (one female salmon) of wild virgin salmon and grilse progeny from spawning years 1967-72.

!...

~ 0:: (j) ::::J 0' :0 P2 c v Q) ~ (j)

0 Q (j) v (f) OJ 01 (])

0

25

-(/) • 1972

"'0 c::: Cl'l (/)

:I 20 0 .s:::. --() • 19 70 Cl'l :I 0" Cl'l 15 -v • 1971 Cl'l

~

0 -(/) c::: 10 '"' :I -<1> "'" Cl'l -c::: 5 <1> ..... 0 a.

e1968

0 0 50 100 150 200

gsper100 in Tobique River

FIG. 6. Total returns to Mactaquac of wild virgin salmon and se spawning years 1967-72 vs. es egg-deposition density the Tobique River.

FEFERENCES

Dominy, C.L. 1973. Hecent changes in Atlantic salmon (Sa~lmo sa.lar) runs in the Light of environmental changes in the Saint John Hiver, New Brunswick, Canada. Biol. Conserv. 5:105-113.

Elson, P.F. 1957. Number of salmon needed to maintain stocks. Can. Fish. Cult. 21:7-17.

Elson, P.F. 1975. Atlantic salmon rivers, smolt production und optimal spawninq: an overview of natural production. Lllt. At . Salmon Found. Spec. Pub]. Ser. 6:96-119.

Environment Canada. 1973. Water quality data report submitted to the Saint John Hiver Basin Board. Prepared by the Water Quality Division, Inland Waters Branch, Ottawa. 473 p.

Francis, A.A. 1980. Densities of juvenile Atlantic salmon and other species, and related data from electroseining studies in the Saint John River system, 1968-78. Freshwater and Anadromous Division, Dept. of Fisheries and Oceans, Halifax, Nova Scotia. Can. Data. Rep. Fish. Aquat. Sci. No. 178. 102 p.

Keachie, P.M. and R.P. C6t~. 1973. Toxic pollutants in the Saint John River Basin. Report #16 from the Saint John River Basin Board, Fredericton, N.B. 179 p.

MacDonald, J .R., R.A. Row and J .R. Machell. 1970. Pollution survey Saint John River syste111, 1969. Unpublished report from the Resource Development Branch, Depart­ment of Fisheries and Forestry, Halifax, N.S. 103 p.

Rugqles, C.P. and W.D. Watt. 1975. Ecologi­cal changes due to hydroelectric develop­ment on the Saint John River. J. Fish. Res. Bd. Canada 32:161-170.

Saunders, D.E. 1969. Water quality studies in the Mactaquac impoundment. Unpub­lished thesis, Department of Civil Enqineerinq, University of New Brunswick, Fredericton, N.B. 69 p.

Sprague, J.B. 1964. Chemical surveys of the Saint John River, tributaries, impoundments, and estuary in 1959 and 1960. Fisheries Research Board of Canada, Manuscript Report Series (O&L) No. 181. 59 p.

Symons, P.E.K. 1979. Estimated escapement of Atlantic salmon (Salmo salar) for maximum smolt production in rivers of different productivity. J. Fish. Res. Bd. Canada 36:132-140.

Watt, W.D., 1973. Aquatic ecoloqy of the Saint John River - Volume l. Report #l5f from the Saint John River Basin Board, Fredericton, N.B. 112 p.

l3

Hatt, W.D., G.ll. Hardinq, ,J. Caldwell and A. McMinn. 1973. Sludqeworms (Oligochaetes) as indicators of water pollution in the Saint John River. Report #15c from the Saint John River Basin Board, Fredericton, N.B. 31 p.